Historia mundial
------------------------------------------ Microsoft Windows Millennium Edition Ayuda para el disco de inicio de emergencia ------------------------------------------- (c) Copyright Microsoft Corporation, 2000 Este documento proporciona informacin complementaria o de ltima hora como suplemento a la documentacin de Windows Millennium Edition (Windows ME). Para cerrar este archivo de Ayuda, presione ALT-A-S. -------- CONTENIDO -------- RESUMEN Si Windows Millennium Edition nicamente se inicia en el modo a prueba de errores TIPOS DE MTODOS Y MEDIOS DE INSTALACION DE WINDOWS MILLENNIUM EDITION Windows Millennium Edition (versin comercial) Windows Millennium Edition (versin de actualizacin) Cmo busca las versiones anteriores de Windows el programa de instalacin de la versin de actualizacin de Windows Millennium Edition Instalaciones limpias Versiones OEM de Windows Millennium Edition SI WINDOWS MILLENNIUM EDITION NO SE INICIA EN EL MODO A PRUEBA DE ERRORES Usar ScanDisk para comprobar el disco duro Usar el Comprobador del Registro de Windows SI EL PROGRAMA DE INSTLACION SE DETIENE Y WINDOWS MILLENNIUM EDITION NO SE INICIA EN EL MODO A PRUEBA DE ERRORES Aviso acerca del software antivirus El programa de instalacin deja de responder durante la deteccin de hardware DESINSTALAR WINDOWS MILLENNIUM EDITION INSTALAR WINDOWS MILLENNIUM EDITION CON WINDOWS NT O WINDOWS 2000 INSTALAR WINDOWS MILLENNIUM EDITION EN UN DISCO DURO NUEVO ======= RESUMEN ======= Si tiene problemas para instalar o iniciar Windows Millennium Edition intente iniciar el equipo en el modo a prueba de errores antes de intentar los pasos que se indican en este documento. Si puede iniciar el sistema en el modo a prueba de errores, consulte el Solucionador de problemas de modo a prueba de errores de Windows Millennium Edition, en la p gina de advertencia de Modo seguro. En el modo a prueba de errores, puede utilizar las herramientas de resolucin de problemas de Windows, como Restaurar sistema, que no est n disponibles al iniciar el equipo desde este disco de inicio. Para iniciar Windows en modo a prueba de errores: 1. Extraiga el disco de inicio y reinicie el equipo. 2. Cuando arranque de nuevo el equipo, presione la tecla CTRL y mantngala as hasta que aparezca el men de inicio de Microsoft Windows Millennium Edition. 3. En el men Inicio, elija Modo a prueba de errores (opcin 3). 4. Siga los pasos que se indican en el Solucionador de problemas del modo a prueba de errores. Si Windows Millennium Edition nicamente se inicia en el modo a prueba de errores --------------------------------------------------------- Si sigui los pasos indicados en el Solucionador de problemas del modo a prueba de errores y, an as, no puede iniciar Windows con normalidad, siga estos pasos: 1. Cierre este archivo de Ayuda. 2. En el smbolo del sistema, escriba: scanreg /restore y presione ENTRAR. 3. Seleccione la fecha de copia de seguridad mas reciente y, a continuacin, haga clic en Restaurar. Si realiza estos pasos y sigue sin poder reiniciar el equipo con normalidad: 1. Utilice el disco de inicio de Windows Millennium Edition para reiniciar el equipo y seleccione la opcin 1 en el men de inicio y, a continuacin, haga presione ENTRAR. 2. Cierre el archivo de Ayuda. 3. Siga las instrucciones que aparecen en la pantalla para intentar instalar de nuevo Windows Millennium Edition. ********** IMPORTANTE: Si instal algn programa incluido con su disco duro, asegrese de leer la documentacin que describe cmo iniciar el equipo con un disco de inicio. ********** ====================================================================== TIPOS DE MTODOS Y MEDIOS DE INSTALACION DE WINDOWS MILLENNIUM EDITION ====================================================================== La siguiente seccin describe las diferentes versiones de Windows Millennium Edition y sus requisitos de instalacin. Windows Millennium Edition (versin comercial) ---------------------------------------------- Esta versin no requiere una versin anterior de Microsoft Windows. Windows Millennium Edition (versin de actualizacin) ----------------------------------------------------- El programa de instalacin requiere una copia anterior de Microsoft Windows 95 Windows 98. Cmo busca las versiones anteriores de Windows el programa de instalacin de la versin de actualizacin de Windows Millennium Edition -------------------------------------------------------------------------- El programa de instalacin busca en su equipo un producto que le permita realizar la actualizacin. Si el programa de instalacin no encuentra una versin anterior de Windows en su equipo, le pedir que inserte el medio de la versin anterior para confirmar que puede realizar la actualizacin. El medio puede ser un CD-ROM, un disco o una carpeta del disco duro en la que se encuentren los archivos de instalacin. Si utiliza discos, el programa de instalacin podra pedirle varios de ellos. Instalaciones limpias ---------------------- Puede utilizar la versin de actualizacin de Windows Millennium Edition para instalar Windows Millennium Edition en un equipo que no tenga instalada una versin anterior de Windows, como sucede despus de formatear el disco duro. Esta opcin se suele denominar "instalacin limpia". Como el proceso de comprobacin de conformidad no puede encontrar una versin anterior, el programa de instalacin le pedir que inserte el medio de la versin anterior para confirmar que puede realizar la actualizacin. El medio puede ser un CD-ROM, un disco o una carpeta del disco duro en la que se encuentren los archivos de instalacin. Si utiliza discos, el programa de instalacin podra pedirle varios de ellos. Para obtener mas informacin acerca de cmo instalar Windows Millennium Edition en un equipo en el que no haya un sistema operativo anterior, consulte "Cmo instalar Windows Millennium Edition en un disco duro nuevo", al final de este documento. Versiones OEM de Windows Millennium Edition ------------------------------------------- La versin de Windows Millennium Edition para fabricantes de equipos originales (OEM) es una versin comercial especial a disposicin de los fabricantes de equipos. Los OEM pueden personalizar estas versiones de Windows Millennium Edition para su hardware y software. Los procedimientos y requisitos de instalacin que se describen en este documento pueden ser diferentes si dispone de una versin OEM de Windows Millennium Edition. Para obtener mas informacin, lea la documentacin incluida con su equipo o pngase en contacto con el fabricante del mismo. ========================================================================= SI WINDOWS MILLENNIUM EDITION NO SE INICIA EN EL MODO A PRUEBA DE ERRORES ========================================================================= Las siguientes condiciones pueden hacer que Windows Millennium Edition no se inicie en el modo a prueba de errores: - El equipo fue infectado por un virus. Utilice software antivirus actualizado para comprobar si hay un virus y limpiar el equipo si es necesario. - La configuracin del CMOS del equipo no es correcta. Compruebe si la configuracin del CMOS del equipo es correcta. Tenga en cuenta que puede necesitar ponerse en contacto con el fabricante del equipo para comprobar la configuracin. - Existe un error en el hardware. Tenga en cuenta que puede necesitar ponerse en contacto con el fabricante del equipo para obtener mas informacin acerca del hardware. - Existe un error en el disco duro del equipo. Consulte "Usar ScanDisk para comprobar el disco duro". - Existe un error en el Registro de Windows. Consulte "Usar el Comprobador del Registro de Windows". Usar ScanDisk para comprobar el disco duro ------------------------------------------ Si cree que existen daos en algn archivo o algn problema de otro tipo en su disco duro, ejecute ScanDisk para comprobarlo y reparar los errores. Para comprobar en todos los discos duros si hay errores: 1. En el smbolo del sistema, escriba: scandisk /all 2. Presione ENTRAR. Para realizar una comprobacin de superficie completa en todos los discos duros y conseguir la m xima proteccin ante la prdida de datos: 1. En el smbolo del sistema, escriba: scandisk /all /surface 2. Presione ENTRAR. Usar el Comprobador del Registro de Windows ------------------------------------------- Si an as no puede iniciar Windows Millennium Edition en el modo a prueba de errores, ejecute l Comprobador del Registro de Windows (Scanreg.exe), ya que podra haber un problema en el Registro de Windows. Para iniciar el Comprobador del Registro de Windows: 1. En el smbolo del sistema, escriba: scanreg /restore 2. Presione ENTRAR. Es posible que Scanreg no est disponible si Windows Millennium Edition no se instal correctamente en el equipo. ========================================================================= SI EL PROGRAMA DE INSTLACION SE DETIENE Y WINDOWS MILLENNIUM EDITION NO SE INICIA EN EL MODO A PRUEBA DE ERRORES ========================================================================= La siguiente seccin explica lo que puede hacer para recuperar la instalacin de Windows despus de un error. Para obtener mas informacin acerca de otros problemas de instalacin, consulte el archivo instalar.txt que encontrar en la carpeta Win9X del CD de Windows Millennium Edition. Si encuentra alguno de estos mensajes de error al ejecutar el programa de instalacin: - Disco de sistema no v lido - Versin incorrecta de MS-DOS - El archivo Command.com est daado o no se encuentra es probable que deba actualizar los archivos del sistema en el disco de inicio de su equipo. Algunas opciones de configuracin del CMOS o software antivirus pueden impedir que el programa de instalacin de Windows instale en su equipo los archivos de sistema correctos. Para sustituir los archivos de sistema: 1. Utilice el disco de inicio de Windows Millennium Edition para reiniciar el equipo y seleccione la opcin 1 en el men de inicio y, a continuacin, haga presione ENTRAR. 2. Cierre el archivo de Ayuda. 3. Siga las instrucciones que aparecer n en la pantalla para ejecutar el programa de instalacin. 4. Si se le pide, seleccione "Usar modo protegido". Aviso acerca del software antivirus ----------------------------------- Si hay algn programa antivirus en ejecucin durante la instalacin, es posible que impidan que el programa de instalacin actualice correctamente los archivos del sistema. ********** IMPORTANTE: Durante la instalacin, es posible que aparezca un mensaje de advertencia, que le informa de que cambi el registro de arranque u otros archivos. Si aparece ese mensaje, DEBE ACEPTAR los cambios o el programa de instalacin no podr actualizar los archivos importantes que utiliza Windows Millennium Edition para iniciar el equipo. ********** El programa de instalacin deja de responder durante la deteccin de hardware ---------------------------------------------------------------------------- - Si el programa de instalacin deja de responder durante la deteccin del hardware del equipo, apague el equipo, espere unos segundos y encindalo de nuevo. Es posible que necesite hacerlo varias veces. Si se le pide, seleccione "Usar modo protegido" al iniciarse el programa de instalacin. El programa de instalacin podra dejar de responder durante varios de los mdulos de deteccin y omitir las reas en las que se produzcan errores para poder finalizar correctamente. ********** IMPORTANTE: Utilice el interruptor del equipo para apagarlo por completo. No utilice el botn de reinicio ni presione CTRL+ALT+SUPR para reiniciar el equipo. ********** Si, an as, el programa de instalacin no finaliza correctamente, puede que sea necesario iniciar el equipo en el modo a prueba de errores para que pueda ver los temas de Ayuda acerca de la deteccin de hardware. ====================================== DESINSTALAR WINDOWS MILLENNIUM EDITION ======================================= Si los pasos anteriores no funcionan, puede probar a desinstalar Windows Millennium Edition y volver a la versin anterior de Windows. Para desinstalar Windows Millennium Edition, debi elegir guardar la informacin de desinstalacin durante en el programa de instalacin de Windows Millennium Edition. La informacin de desinstalacin se guarda en los archivos Winundo.dat y Winundo.ini. Si elimina estos archivos no podr desinstalar Windows Millennium Edition. ********** IMPORTANTE: no intente desinstalar Windows Millennium Edition si la informacin de particin de su disco duro cambi desde la ltima instalacin correcta de Windows Millennium Edition. Windows Millennium Edition crea una copia de seguridad de la informacin de la particin del disco duro en el archivo Suhdlog.dat al terminar una informacin correcta, y Uninstal.exe restaura en el disco duro la informacin de particin que encuentra en Suhdlog.dat. Si la informacin de particin del disco duro cambi desde la ltima instalacin correcta (en concreto, desde que se cre Suhdlog.dat), es posible que pierda parte de los datos, o todos ellos, al intentar desinstalar Windows Millennium Edition. ********** Para desinstalar Windows Millennium Edition: 1. Utilice el disco de inicio de Windows Millennium Edition para reiniciar el equipo y seleccione la opcin 1 en el men de inicio y, a continuacin, haga presione ENTRAR. 2. Cierre el archivo de Ayuda. 3. En el smbolo del sistema, escriba cada una de las siguientes lneas y presione ENTRAR despus de cada una de ellas. smartdrv: cd\ \command uninstal.exe NOTA: es la letra de la unidad en la que se encuentra la carpeta Windows (la predeterminada es C). es el nombre de la carpeta de Windows (el predeterminado es "Windows"). 4. Escriba S cuando se le pregunte si desea continuar. Este proceso puede durar varios minutos. NOTA: SmartDrive (Smartdrv.exe) no es necesario para ejecutar Uninstal.exe, pero acelera mucho el proceso. ================================================================= INSTALAR WINDOWS MILLENNIUM EDITION CON WINDOWS NT O WINDOWS 2000 ================================================================= No puede instalar Windows Millennium Edition sobre una versin de Windows 2000 o Windows NT, pero ambas pueden coexistir en un mismo sistema. No obstante, por motivos de compatibilidad, se recomienda que instale cada versin en un disco duro o particin diferente. Si Windows NT ya est instalado, el programa de instalacin de Windows Millennium Edition se agregar al men de inicio de Windows NT para permitir alternar entre el inicio de Windows Millennium Edition y de Windows NT. =========================================================== INSTALAR WINDOWS MILLENNIUM EDITION EN UN DISCO DURO NUEVO =========================================================== Consulte el documento "Instalar Windows Millennium Edition en un disco duro nuevo", que encontrar en :\Win9x\Cleanhd.Txt. Tambin puede resultarle til el archivo lame del programa de instalacin. Se encuentra en :\Win9X\instalar.txt. Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net Welcome to the Great Internet Mersenne Prime Search! In case you ever forget, the URL is http://www.mersenne.org/prime.htm. My email address is woltman@magicnet.net. For networking questions, contact Scott Kurowski at primenet@entropia.com. FILE LIST --------- readme.txt This file. prime95.exe The program to factor and run Lucas-Lehmer tests on Mersenne numbers. rpcnet.dll Communicates with the Internet PrimeNet server using RPCs. httpnet.dll Communicates with the Internet PrimeNet server using HTTP. whatsnew.txt A list of new features in prime95.exe. prime.ini A file containing your preferences. The menu choices and dialog boxes are used to change your preferences. local.ini Like prime.ini, this file contains more preferences. The reason there are two files is discussed later. worktodo.ini A list of exponents the program will be factoring and/or Lucas-Lehmer testing. results.txt Prime95.exe writes its results to this file. prime.log A text file listing all messages that have been sent to the PrimeNet server. prime.spl A binary file of messages that have not yet been sent to the PrimeNet server. pnnnnnnn & Intermediate files produced by prime95.exe to resume qnnnnnnn computation where it left off. database This optional binary file is downloaded separately. You only need this file if you are not using the PrimeNet server. It contains all the Mersenne exponents that still need testing. WHAT IS THIS PROGRAM? --------------------- This program is used to find Mersenne Prime numbers. See http://www.utm.edu/research/primes/mersenne.shtml for a good description of Mersenne primes. Mersenne numbers can be proved composite (not prime) by either finding a factor or by running a Lucas-Lehmer primality test. INSTRUCTIONS ------------ There are two ways to use this program. The automatic way uses a central server, which we call the PrimeNet server, to get work to do and report your results. Anyone with Internet access, including AOL, CompuServe, and dial-up ISP users should use this method. You do not need a permanent connection to the Internet. The second method is the manual method. It requires a little more work and monitoring. I recommend this for computers with no Internet access or with some kind of firewall problem that prevents the automatic method from working. If you are running this program at your place of employment, you should first GET PERMISSION from your network administrator or boss. This is especially true if you are installing the software on several machines. Some companies are reluctant to run any software they are not familiar with. INSTRUCTIONS FOR THE AUTOMATIC METHOD ------------------------------------- 1) Download and unzip prime95.zip. You've probably done this already since you are reading this file. 2) Connect to the Internet. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Optionally enter a user ID and password. An easy-to-remember user ID will be helpful if you plan to visit the PrimeNet server's web page to view reports on your progress. If you do not enter a user ID or if you pick a user ID that is already in use, then the server will assign a user ID. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, leave the "Use Primenet..." checkbox checked. Do not turn this checkbox off even if you disconnect from the Internet. Check the "Use a dial-up..." checkbox if you use a modem to connect to the Internet. Note that prime95 will not dial-up to connect to the Internet, rather it waits for a time when you are already connected to contact the server. Click OK. Prime95 will now contact the PrimeNet server to get some work for your computer to do. 4) If you cannot contact the PrimeNet server, then a firewall may be preventing the RPCs from getting to the server. In this case, you may want to try the HTTP-based DLL. Choose "Use HTTP-based DLL" from the Test/Primenet dialog. 4a) If you now get the error message "Unable to load HTTPNET.DLL", then you are probably missing WININET.DLL. This DLL is shipped with Microsoft's Internet Explorer. It is also installed by default in later versions of Windows 95 and Windows NT. You can download and install WININET.DLL from Scott Kurowski's web site. See http://entropia.com/ips/faq.html#wininet for details. 4b) If the http-based DLL will not connect to the server, then you will have to use the manual method described below. There have been reports that the http-based DLL does not work in all MS IE 3.0 environments - we are working on making this DLL work in as many different environments as possible. 4c) If a proxy server is the cause of your connection troubles, see the later section on "SETTING UP A PROXY SERVER". 5) Create a shortcut to prime95.exe and place it in the startup folder. Alternatively, you can install prime95.exe as a Windows 95 service using the Options menu. Prime95 will now run every time you boot your computer. MANUAL METHOD INSTRUCTIONS #1 ----------------------------- 1) Use the Web (http://entropia.com/ips/manualtests.html) to create a userid for yourself and to get a set of exponents to work on. Copy these exponents to a file called worktodo.ini 2) Run prime95.exe. You will see 3 dialog boxes: 2a) In the first dialog box, enter your name and email address. Click OK. 2b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 2c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 3) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 4) Once a month or when done with your exponents, use the web pages again to send the file "results.txt" to the PrimeNet server. It is important to do this so the exponents you are testing are not reassigned to someone else. MANUAL METHOD INSTRUCTIONS #2 ----------------------------- 1) Download and unzip database.zip (http://www.mersenne.org/range2.htm). 2) Use the Web (http://www.mersenne.org/range2.htm) to select a range of exponents to test. Send me e-mail on the range you've chosen. This prevents others from testing the same range. 3) Run prime95.exe. You will see 3 dialog boxes: 3a) In the first dialog box, enter your name and email address. Click OK. 3b) In the second dialog box, change the CPU type and speed if necessary. Fill in roughly how many hours a day you leave your computer running. Click OK. 3c) In the third dialog box, uncheck "Use PrimeNet to get work and report results", click OK. 4) Choose Test/Manual Operation from the menus. Enter the type of work and range of exponents you selected in step 2. 5) Create a shortcut to prime95.exe and place it in the startup folder. Prime95 will now run every time you boot your computer. 6) Once a month or when done with your range, send the file "results.txt" to woltman@magicnet.net. It is important to do this so the exponents you've tested can be removed from the master list. NOTES ----- Let prime95.exe run at all times. It runs at the lowest possible priority, making use of all your idle CPU cycles. It should not interfere with your normal work. Let the program run overnight and on weekends. Never turn your computer off. Turn off your monitor to conserve energy. NOTE: Running your computer non-stop could increase your electric bill by $30 per year or more. It can take many CPU days to test a large Mersenne number. This program can be safely interrupted by using the ESC key to write intermediate results to disk. This program also saves intermediate results to disk every 30 minutes in case there is a power failure. To fully utilize a dual Pentium machine, you must run two copies of prime95.exe. Run one copy of prime95 as described above. Run the second copy of prime95.exe with the -A1 switch. Place two shortcuts in the startup folder (one with no switch and one with the -A1 switch). Dual processor machines can also improve performance by setting processor affinity in Windows NT. To do this, do the following: 1) Run Windows NT task manager 2) Click on the processes tab 3) Find your PRIME95 processes 4) Right click on the processes and pick Processor Affinity. 5) Set the flag on CPU 0 for one process and CPU 1 for the other You can compare your computer's speed with other users by checking the site http://www2.tripnet.se/~nlg/mersenne/benchmk.htm. If you are much slower than comparable machines, download Microsoft's WinTop kernel toy to find programs (such as AOL) that are stealing all of prime95's CPU cycles. You can download the software free at http://www.microsoft.com/windows/downloads/contents/powertoys/w95procwatcher You can get a report of your PrimeNet server account status on the web (http://entropia.com/primenet/status.shtml). Type your UserID and password into the web form, and click "Get Account Report". You can get your UserID and password from the Test/User Information dialog box. Information about running a local PrimeNet server is also available. See http://entropia.com/primenet. If you have any questions about the PrimeNet server, you can send e-mail to primenet@entropia.com. The first time you run this program it will perform an hour long self-test to make sure the Lucas-Lehmer code is running properly on your system. There are 16 different self-tests, one for each FFT size. You can run all 16 self-tests with Options/Self Test menu choice. This is not required. If you have overclocked your machine, I highly recommend running the torture test for a couple of days. The longer you run the torture test the greater the chance that you will uncover an error caused by overheating. Depending on the exponent being tested, the program may decide that it would be wise to invest some time checking for small factors before running a Lucas-Lehmer test. Furthermore, the program may start factoring exponents before a previous Lucas-Lehmer test completes. This is normal! The program will resume the Lucas-Lehmer test when the factoring completes. For manual users, once you've started testing a range there is no advantage in downloading a new database. After your range completes, you can download a new database before you start your next range. You can configure this program to have different properties at different times of the day and/or to not run during certain times of the day. Unfortunately, you must manual edit the prime.ini file. Let's say you want to install the program on a friend's machine and he runs a screen saver at night. He also runs a disk defragmenter at midnight on weekdays. This prime.ini file will run the program at a higher priority than his screen saver at night and on weekends. It also sleeps for an hour when his defragmenter starts running. Finally, at night fewer save files are generated to allow his disk to stay powered down longer. UserID=foo Time=1-5/8:30-17:30 Priority=1 DiskWriteTime=30 Time=1-5/1:00-8:30,1-5/17:30-24:00,6-7/0:00-24:00 Priority=5 DiskWriteTime=240 The 1-5 refers to days of the week, with Monday=1 and Sunday=7. The time portion refers to the hours of the day based on a 24-hour clock. You do not need to specify days of the week (e.g. Time=1-7/0:00-8:00 is the same as Time=0:00-8:00). Unpredictable results will occur if there are overlapping time intervals. Also note that any options that appear in the Time= sections should not appear earlier in the prime.ini file and you can no longer edit these options from theuser interface. SETTING UP A PROXY SERVER ------------------------- Create a file in the same local folder as Prime95.exe, called "primenet.ini". Add these text lines, substituting the appropriate proxy server URL and port: [PrimeNet Proxy] ProxyHost=http://proxy.megacorp.com:8080 If the proxy is secured by a userid/password, add the following two text lines, substituting the appropriate values: ProxyUser=whatever_the_userid_is ProxyPass=whatever_the_password_is After the first time PrimeNet is contacted through a secure proxy, the proxy password is encoded and a new parameter 'ProxyMask=1' set. To change the password, simply change the ProxyPass= value, and either delete the ProxyMask text line or set ProxyMask=0. PROGRAM OUTPUT -------------- On screen you will see: Factored M400037 through 17517*2^32 (pass 3 of 16). Clocks: 24235224=0.121 sec. This means prime95 is in the third pass of a 16 pass process to find a small factor of 2^400037-1. Iteration: 941400 / 1667747. Clocks: 21889762 = 0.109 sec. This means prime95 just finished the 941400th iteration of a Lucas-Lehmer primality test. The program must execute 1667747 iterations to complete the primality test. The average iteration took 21889762 "clock cycles" or 0.109 seconds. The results file and screen will include lines that look like: M2645701 has a factor: 13412891051374103 This means to 2^2645701-1 is not prime. It is divisible by 13412891051374103. M2123027 no factor to 2^57, WS1: 14780E25 This means 2^2123027-1 has no factors less than 2^57. The Mersenne number may or may not be prime. A Lucas-Lehmer test is needed to determine the primality of the Mersenne number. WS1 is the program version number. 14780E25 is a checksum to guard against email transmission errors. M1992031 is not prime. Res64: 6549369F4962ADE0. WT1: B253EF24,1414032,00000000 This means 2^1992031-1 is not prime - a Lucas-Lehmer test says so. The last 64 bits of the last number in the Lucas-Lehmer sequence is 6549369F4962ADE0. At some future date, another person will verify this 64-bit result by rerunning the Lucas-Lehmer test. WT1 is the program version number. B253EF24 is a checksum to guard against email transmission errors. 1414032 can be ignored it is used as part of the double-checking process. The final 00000000 value is a set of 4 counters. These count the number of errors that occurred during the Lucas-Lehmer test. M11213 is prime! WS1: 579A579A This means 2^11213-1 is a Mersenne prime! WS1 is the program version number. 579A579A is a checksum to guard against email transmission errors. RUNNING PRIME95 ON SEVERAL COMPUTERS ------------------------------------ The easiest way to do this is to first set up prime95 on one computer. Next copy all the files to the second computer. Delete the local.ini file and worktodo.ini files. These files contain information that is specific to the first computer. Start prime95 on the second computer and optionally use Test/User Information to give the second computer a unique computer ID. Repeat this process for all the computers you wish to run prime95 on. If you do not follow the instruction above, be sure you use Test/User Information to give each computer the same userid and password. Failure to do this will result in all your work being "credited" to different user IDs. TEST MENU --------- The PrimeNet menu choice lets you configure the type of work you get from the server. The "Use PrimeNet..." option can be turned on to switch from the manual method to the automatic method. The "Request whatever..." box should be left checked. However, if you are running a slow computer and don't mind waiting several months for a single Lucas-Lehmer test to complete OR you are running a faster computer and would rather do factoring, then uncheck this box and choose a different type of work to do. The "Days of work to get" should be changed based on how often you connect to the Internet. As long as you connect at least once in the given time period, prime95 will have an uninterrupted stream of work. However, the program will not checkout more than 20 exponents no matter what "Days of work to get" is set at. The Manual Operation menu choice allows you to select a range of exponents to work on. You may also use this menu choice to add to your existing work (e.g. when you are running low on exponents to test). The User Information menu choice lets you change your name and email address. Your name will be used in credits and "top producers" web pages. Your email address will be used to send you warnings if an exponent you have reserved is about to expire and to send you a newsletter once every few months. Select the no email checkbox to stop the server from sending expiration warnings. The userid you use will appear in the status pages on the PrimeNet server. You can also set the ComputerID field if you have several computers and want to keep track of which computers produced which results. The Vacation/Holiday menu choice lets prime95 update the expected completion dates on the PrimeNet server. This will prevent one of your exponents from being reassigned while you're gone. Also, if you are taking a long vacation, prime95 will get extra exponents to test. For example, if you are leaving immediately for a 6 week vacation, connect to the Internet and choose 42 days. If you are leaving in two days for a 6 week vacation, then set choose 44 days. Primenet will send the new completion dates whenever you connect to the Internet over the next 2 days. The Status menu choice will tell you what exponents you are working on. It will also estimate how long that will take and your chances of finding a new Mersenne prime. The Continue menu choice lets you resume prime95 after you have stopped it. The Stop menu choice lets you stop the program. When you continue, you will pick up right where you left off. This is the same as hitting the ESC key. ADVANCED MENU ------------- You should not need to use the Advanced menu. This menu choice is provided only for those who are curious to play with. To avoid confusion for novice users, all the choices in the Advanced menu have been grayed. Please read this section if you want to know what the Advanced menu choices do. To turn on the Advanced menu, use the Advanced Password dialog box and enter a value of 9876. Also note that many of the menu choices are grayed while testing is in progress. Choose Test/Stop to activate these menu choices. The Test choice can be used to run a Lucas-Lehmer test on one Mersenne number. Enter the Mersenne number's exponent - this must be a prime number between 7 and 5259999. The Time choice can be used to see how long each iteration of a Lucas- Lehmer test will take on your computer and how long it will take to test a given exponent. For example, if you want to know how long a Lucas-Lehmer test will take to test the exponent 876543, choose Advanced/Time and enter 876543 for 100 iterations. A Pentium will automatically time and compute the results. 486 owners will need to time how long the operation takes by hand, divide that time by 100 and multiply by 876543 to compute how long a full Lucas-Lehmer test will take. The ECM choice lets you factor small Mersenne exponents using the Elliptic Curve Method of factoring. Select a few exponents and bounds to factor from the http://www.mersenne.org/ecm.htm web page. Note: You do not reserve exponents to work on, several people can do ECM factoring on the same exponent. The program uses a random number generator to select elliptic curves to test. You must email results to me at woltman@magicnet.net - primenet does not support ECM factoring. You can also edit the worktodo.ini file directly. For example: ECM=751,3000000,0,100,0,0,0 The first value is the exponent. The second value is bound #1. The third value is bound #2 - leave it as zero. The fourth value is the number of curves to test. The fifth value is the number of curves completed. The sixth value is the specific curve to test - it is only used in debugging. The seventh value is 0 for 2^N-1 factoring, 1 for 2^N+1 factoring. The Clear Primes choice can be used to remove one or more exponents from the database. You might do this for two reasons: 1) Let's say you're testing range 1234000 to 1234999. If I send you some mail saying that a factor has been found for M1234567, then you use Clear Primes to remove 1234567 from your database so that you won't have to run a Lucas-Lehmer test on it. 2) You downloaded a new database after checking all the exponents between 1234000 and 1234300. You can use Clear Primes to remove the exponents between 1234000 and 1234300. Do not use the Factor menu choice. If you're running Lucas-Lehmer tests on a range or just factoring a range - use Test/Manual Operation. The program will know the optimal amount of factoring to perform. Having said that, if you insist on using this menu choice, you can look for factors less than 2^62 of any Mersenne numbers with an exponent less than 10,000,000. Let's say you're writing a factoring program for a UNIX machine and want to check its results. Use both this menu choice and your UNIX program to search for small factors on a set of Mersenne numbers and compare the results. Round off checking. This option will slow the program down by about 15%. This option displays the smallest and largest "convolution error". The convolution error must be less than 0.49 or the results will be incorrect. There really is no good reason to turn this option on. The Priority menu is used to adjust the priority prime95 runs at. You should not need to change this. You might raise the priority if you (or your coworker) just cannot live without your screen saver (bad idea), or if you are running some ill-behaved program that is using CPU cycles for no good reason. The Manual Communication menu choice should only be used if the automatic detection of an Internet connection is not working for you. Using this option means you have to remember to communicate with the server every week or two (by using this same menu choice). The Quit GIMPS menu choice is used when you no longer want this computer to work on the GIMPS project. You may rejoin at a later date. If you are a PrimeNet user your unfinshed work will be returned to the server. If you are a manual user, you need to send me email containing your results.txt file and a note saying you are quitting. OPTIONS MENU ------------ The CPU menu choice lets you tell the program what kind of CPU you have. The program will normally figure this information out for you. This information is used to give accurate time estimates in the Test/Status menu choice. It is also used, to choose between integer based factoring (Cyrix and 486) and floating point based factoring (Pentium and Pentium Pro). No matter what you choose, the program uses the same code to run the Lucas-Lehmer primality test. If you have an AMD K5 or Cyrix M2 chip, choose Cyrix 6x86. The Preferences menu choice lets you control how often a line is written to the main window. Also how often a line is written to the results file. It also lets you change how often intermediate files (to guard against power failure an crashes) are created. You can control how often the program checks to see if you are connected to the Internet. The program polls whenever it has new data to send to or work to get from the PrimeNet server. If you are low on disk space, you can select one intermediate file instead of two. However, if you crash in the middle of writing the one intermediate file, you may have to restart an exponent from scratch. You can also tell the program to be quiet, rather than beeping like crazy, if a new Mersenne prime is found. The Self Test choice lets you run a sixteen-hour self test. Passing the self-test does not guarantee that you will not run into any hardware problems later on, but it does give you some confidence that the program is working properly. The Torture Test choice will run a continuous self test. This is great for testing machines for hardware problems. The Tray Icon choice will cause prime95 to have a small icon on the taskbar when it is minimized. You can activate the program by double-clicking on the small icon. If you place the cursor over the small icon, a tooltip will display the current status. The No Icon choice is only enabled if the Advanced Menu is activated with the password. Using this menu choice means there will be no prime95 icon on the taskbar once you minimize the program (making it very hard to reactivate!) If you turn this feature on and want to turn it back off, edit prime.ini and change the line "HideIcon=1" to "HideIcon=0", then reboot. Checking the Windows 95 Service menu choice will install prime95 as a service. The program will be run automatically whenever you reboot your machine. You will not need to place a shortcut to prime95 in the startup menu. COMMAND LINE ARGUMENTS ---------------------- These command line arguments can be used to schedule prime95.exe to run only at certain times of the day or at a different priority. Note that raising the program's priority will not make it run any faster on an idle machine. -Tdd:hh:mm This tells the program to terminate itself after the specified number of days, hours, and minutes. The days and hours are optional. For example, use Windows 95 Plus Pack's scheduler to run the program on your co-worker's machine for 12 hours every evening with the -T12:00 argument. -An This is used to run two or more copies of prime95 from the same directory. Using this switch causes prime95 to use a different set of filenames for the INI files, the results file, the log file, and the spool file. Just use a different value of n for each copy of prime95.exe you start. -Wdirectory This tells prime95 to find all its files in a different directory than the executable. POSSIBLE HARDWARE FAILURE ------------------------- If the message, "Possible hardware failure, consult the readme file.", appears in the results file, then prime95's error-checking has detected a problem. Prime95 will continue from the last save file. If you do not get the message, "Disregard last error...", then the problem is not reproducible - a definite sign of hardware problems. How can this be when none of your other programs have problems? The answer is that prime95 stresses your machine more than any other program you run. The operating system usually shuts down the floating-point unit when no programs are using it. Prime95 continuously uses the FPU, consuming more electricity and generating more heat. If the CPU is not properly cooled, errors can occur. Prime95 also constantly accesses main memory - up to 60MB per second. This constant activity will detect memory problems that other programs do not. This is why Cray Research has used a program similar to this one as part of its supercomputer diagnostics package for over a decade. Could it be a software problem? If the error is ILLEGAL SUMOUT, then there is a good chance that this is a software problem. A device driver or VxD may not be saving and restoring CPU state correctly. The good news is that prime95 recovers very well from ILLEGAL SUMOUT errors. Try seeing if the problem occurs only when a specific device is active or a specific program is running. How can you track down the hardware problem? Unfortunately, this is not easy. To see if your CPU is overheating, run prime95 for several hours. Open the box. Is the CPU too hot to touch? If so, a heat sink or CPU fan should solve the problem. Memory problems are not as easy to diagnose. My only advice is to try swapping memory SIMMs with a coworker's or friend's machine. If the errors go away, then you can be confidant that the original problems were memory related. What can you do if you are unwilling or unable to find the hardware problem? If you are only getting an error once in a while, then your results are probably OK. The error-checking code is not infallible, so your results will need to be double-checked. If you are getting several errors during each primality test, then I would recommend using your machine to factor Mersenne numbers. LUCAS-LEHMER DETAILS -------------------- This program uses the Lucas-Lehmer primality test to see if 2**p-1 is prime. The Lucas sequence is defined as: L[1] = 4 L[n+1] = (L[n]**2 - 2) mod (2**p - 1) 2**p-1 is prime if and only if L[p-1] = 0. This program uses a discrete weighted transform (see Mathematics of Computation, January 1994) to square numbers in the Lucas-Lehmer sequence. DISCLAIMER ---------- THIS PROGRAM AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE. THANKS ------ Happy hunting and thanks for joining the search, George Woltman woltman@magicnet.net