New features in Version 21.3 of prime95.exe ------------------------------------------- 1) The program will now skip the P-1 factoring stage if another user has already performed this step. 2) The Advanced/Quit GIMPS menu choice now lets you quit after current work completes or quit immediately. New features in Version 21.2 of prime95.exe ------------------------------------------- 1) The program now uses the SSE2 instructions introduced on the Pentium 4 CPU. This version is about 3 times faster than the previous version on a P4. 2) The program now uses the prefetch instructions on the Celeron 2, Pentium 3, and all Athlon CPUs. This results in about a 20% performance boost on these machines. 3) Process priority is now set to idle. Microsoft documentation says that an idle thread priority overrides process priority. The program's priority scheme has always worked well. However, several Win2K users have reported that the program works better if the process priority is also set to idle. 4) The program now delays calculations until 90 seconds after bootup. This lets your machine boot up as fast as possible. This can be changed, see undoc.txt. 5) The default crossover between double-check assignments and first-time tests has been increased to a 400 MHz PII. 6) After 5 1/2 years, a help file now exists! It is HTML Help which may have problems on older Windows machines. If so, try downloading hhupd.exe from Microsoft's web site. 7) The program used to do factoring and P-1 testing on new exponents before completing LL tests on older exponents. This was confusing to many. The program now processes the worktodo.ini file in sequential order. See undoc.txt on how to restore the old behavior. 8) Error messages such as ILLEGAL SUMOUT, SUMINP != SUMOUT, etc. are no longer sent to the server since the final result contains a count of how many errors occured during the LL test. 9) Some of the FFT crossover points have changed slightly. 10) Test/Status now outputs the day of the week each work item will complete. 11) Interim output lines have changed - hopefully, so they are more useful especially to newbies. By default, output lines no longer contain the clocks count. Lines now contain a timestamp. Benchmark timings are now output in milliseconds. These defaults can be changed using options in undoc.txt. 12) A new welcome screen for new users will encourage stress testers to use the program without reserving exponents. 13) There is now a menu choice that lets you unreserve a specific exponent. This is for knowledgable users only. You might do this if the server assigned a small exponent and you'd rather be testing larger ones. Or the prime95 you set up on another machine had a hard drive failure. 14) The Windows 9x Service menu choice has been replaced by the more general Start at Bootup menu choice. This choice now sets registry entries to autostart prime95 on any Windows machine. WARNING: Using this option will delete any StartUp menu shortcuts so the registry entry and startup menu do not both try to start prime95. 15) Prime95 will now ask for confirmation if you enter a CPU speed that differs from the computed CPU speed by more than 4%. 16) The self-test menu choice was deleted - use the torture test instead. 17) A benchmark menu choice has been added. 18) The torture test code now includes more FFT lengths including smaller ones that run completely in the L2 cache which may increase CPU temperatures. Each FFT size is tested for 15 minutes by default. There are now several options in the undoc.txt for fine tuning the torture test's behavior. New features in Version 20.6 of prime95.exe ------------------------------------------- 1) A crash bug was fixed. If you did P-1 factoring followed by trial factoring, then if you found a factor unallocated memory was accessed usually resulting in a crash. New features in Version 20.5 of prime95.exe ------------------------------------------- 1) A rare error was fixed. When the memory settings changed during the GCD step in P-1 or ECM factoring, then a spurious "ERROR: Factor does not divide N!" error was raised. New features in Version 20.4 of prime95.exe ------------------------------------------- 1) If stage 2 of P-1 was postponed because of insufficient memory, the program did not restart stage 2 when nighttime started. This bug was fixed. 2) By default, PII-300's and faster get first-time LL tests, P-90 and faster get double-checking work, and all slower machines get factoring work. 3) An ECM bug during stage 2 init on huge exponents caused false ILLEGAL SUMOUT errors. This bug was fixed. New features in Version 20.3 of prime95.exe ------------------------------------------- 1) Another fairly uncommon ECM bug was fixed. The bug caused "Factor does not divide N!" errors. 2) A couple of minor bugs in computing the optimal P-1 bounds to use prior to a Lucas-Lehmer test were fixed. The program now does a better job at estimating the memory required in P-1 stage 2. Finally, although P-1 stage 2 working set size is unchanged, the program allocates less memory in stage 2. 3) Prime95 no longer searches for a smaller factor when trial factoring discovers a factor. The reasons are two-fold. 1) Version 19 had a bug where stopping and restarting the program bypassed the search for smaller factors. Thus, my database may already be missing smaller factors. 2) As we factor larger exponents to a deeper depth it may no longer be a quick job to determine if there are smaller factors. Note, that version 20 will still look for smaller factors if you are looking for factors below 2^60 with the FactorOverride option in undoc.txt. 4) The undocumented AMPM feature controls how times are formatted in the Options/CPU dialog box. New features in Version 20.2 of prime95.exe ------------------------------------------- 1) If P-1 stage 1 completed and there was not enough memory to start stage 2 immediately, then an incorrect save file was generated. This bug was introduced in version 20.1. Upon restart of the P-1 factoring job a crash or other unpredictable behavior was possible. This bug was fixed and this version has special code to properly read these incorrect save files. 2) P-1 will restart any time the memory settings change. This is done so that the optimal P-1 bounds can be computed with the new memory settings. 3) A bug in ECM testing was fixed. New features in Version 20.1 of prime95.exe ------------------------------------------- 1) A bug in the new GCD code was fixed. 2) Timings in the P-1 stage are no longer cumulative. There is a new feature in undoc.txt for those that prefer cumulative timings. 3) Messages are now output prior to beginning the lengthy GCD. 4) The FactorOverride undocumented feature (not for use with PrimeNet) now supports factoring to a deeper level than prime95 would ordinarily factor. 5) A bug where the worktodo.ini entry was not removed if P-1 found a factor was fixed. 6) If P-1 finds a factor it now deletes any Lucas-Lehmer intermediate files. 7) A crash bug when continuing from a P-1 stage 2 save files with different available memory parameters was fixed. 8) Resuming an LL test now outputs a line to the screen, 9) The Test/Status display now correctly calculates the estimated completion time for an LL test when P-1 factoring is in progress. 10) Advanced/Factor menu choice was deleted. 11) A bug in computing P-1 stage 2 percentage complete was fixed. New features in Version 20.0 of prime95.exe ------------------------------------------- 1) The program now does some P-1 factoring prior to running first time and double-checking Lucas-Lehmer tests. This will increase overall GIMPS throughput. If you install version 20 in the middle of an LL test the program will run the P-1 step if the LL test is less than 50% complete. 2) The Options/CPU dialog box now asks how much memory the program can use during the P-1 factoring. See the "Setting Available Memory" section in the readme.txt file. 3) Stage 1 of P-1 factoring is now faster. 4) The GCD used in P-1 and ECM factoring is now faster. 5) The Test/Manual Operation menu choice has been deleted. 6) The memory options in P-1 and ECM dialog boxes have been deleted. 7) The "send new completion dates" checkbox was moved from the Test/Primenet dialog box to the Advanced/Manual Communication dialog box. 8) A bug in estimating time remaining for a factoring job was fixed. 9) AdvancedFactor now writes a line to the worktodo.ini - just like all the other work types. 10) ECM and P-1 are now consistent with Lucas-Lehmer testing in the use of the "Iterations between screen outputs" setting. An iteration is defined as the time it takes to do a squaring. If you are doing ECM on small exponents you will probably want to increase this setting. New features in Version 19.2 of prime95.exe ------------------------------------------- 1) A bug in factoring exponents above 35.79 million was fixed. New features in Version 19.1 of prime95.exe ------------------------------------------- 1) A new undocumented feature, Stage1GCD, lets you speed up P-1 tests on large exponents - see undoc.txt for details. 2) K6 CPUs now default to the Pentium code path instead of the Pentium Pro code path. This is faster on the K6. 3) The rolling average formula was adjusted to work better on machines that are not on 24 hours a day. New features in Version 19.0 of prime95.exe ------------------------------------------- 1) Faster - in some cases as much as 10% faster!. The FFTs were recoded for improved memory and TLB efficiency. Furthermore, optimizations specific to the Pentium Pro and later processors were added. 2) New FFT lengths. The program can now test exponents as large as 79.3 million. Also, smaller FFT lengths are supported for use in ECM and P-1 factoring. 3) More conservative FFT breakpoints. This could actually result in some exponents being slower to test in this version. However, the chance of a fatal rounding error has been reduced. 4) P-1 factoring has been added. Although it is not very practical for large exponents because of a slow GCD routine, it can be used to find new factors of exponents below a few million or so. 5) ECM can now run on large exponents. Once again, the slow GCD routine and high memory requirements might make this impractical for large exponents. 6) ECM and P-1 factoring now support save files. Very handy on lengthy runs. The count of completed ECM curves is maintained in the save file instead of the worktodo.ini file. 7) ECM and P-1 factoring lets you specify the amount of memory to use. In some cases, more memory can improve execution speed slightly. 8) A bug in guessing the CPU speed on initial install has been fixed. 9) The preferences dialog now has an option to pause prime95 when a laptop is running on its battery. 10) Error checking has been improved slightly. 11) Factoring is now "layered". That is, prime95 now factors to 2^50, then 2^51, 2^52, and so forth up to the appropriate limit. The factoring output lines have been changed to show percent complete in the current "layer". 12) A bug in running two or more self or torture tests in the same directory has been fixed. 13) Trial factoring above 2^64 is now supported. 14) More trial factoring is now done to take into account the cost of double-checking. 15) Title now contains percent complete when LL testing. By default, the percent complete value is now displayed to 2 decimal places. You can change this by setting PercentPrecision in prime.ini to a value between 0 and 6. 16) Affinity and service name settings moved from prime.ini to local.ini file. Prime95 will automatically move these settings for you. 17) An option to get only 10,000,000 digit numbers to run primality tests on has been added to the Test/Primenet dialog box. See http://www.mersenne.org/prize.htm for rules on claiming the EFF award for finding a 10,000,000 digit prime. 18) The Advanced/Clear primes menu choice has been deleted. 19) The prime95 icon turns yellow when the program is idle. After an error such as ILLEGAL SUMOUT, the icon will blink for 10 seconds. 20) The User Information dialog box allows you to request newsletters and form a team user ID where the team members cannot alter the team name. 21) A bug in the reporting of error counts in the results.txt file has been fixed. 22) The server can now broadcast important messages to the prime95 client. Prime95 will blink the icon until prime95 is activated and then it will display the message. 23) A computer ID will be generated for computers that do not have one. If you want to assign your own computer ID, please try to make each computer ID using the same user ID unique. New features in Version 18.1 of prime95.exe ------------------------------------------- 1) Added code so that server can distinguish between a v17 and v18 client. 2) Only v17 save files above 4194304 are deleted. New features in Version 18.0 of prime95.exe ------------------------------------------- 1) Bug fixed in Lucas-Lehmer testing of exponents above 4194304. New features in Version 17.2 of prime95.exe ------------------------------------------- 1) Faster 2^N+1 ECM factoring. New features in Version 17.1 of prime95.exe ------------------------------------------- 1) The -T command line switch has been deleted. 2) You can now fine tune your control of the program by adding Time= lines to your prime.ini file - see the readme.txt file. 3) ECM factoring for 2^N+1 is now available. 4) By default, ECM factoring stops if a factor is found for exponents above 5825 and continues (if the cofactor is composite) for exponents below 5825. You can override this behavior by setting ContinueECM=0 or 1 in prime.ini. New features in Version 17.0 of prime95.exe ------------------------------------------- 1) Prime95 can now be used to double-check its own results. 2) Machines less powerful than a P133 will default to double-checking assignments. 3) The total number of errors that occur during the Lucas-Lehmer test are now output in results.txt. New features in Version 16.5 of prime95.exe ------------------------------------------- 1) A new httpnet.dll can provide Scott Kurowski with debugging information. Simply create a primenet.ini file with these lines: [Debug] PacketLog=1 Output file is pnHttp.txt. 2) The old network retry time has been replaced by two settings. The modem retry time (default 2 minutes) controls how often prime95 polls your modem to see if you are connected to the Internet. The network retry time (default 60 minutes) controls how long prime95 waits after a failed attempt to contact the server. 3) A timestamp and program version number is written to the prime.log file. 4) You can now switch between HTTP-based and RPC-based PrimeNet protocols from the Test/Primenet dialog box. New features in Version 16.4 of prime95.exe ------------------------------------------- 1) Lucas-Lehmer testing output now shows percent complete. 2) Windows NT users can now set processor affinity on multi-CPU systems. 3) ECM factoring is available for small exponents. See http://www.mersenne.org/ecm.htm for a list of exponents that need factoring. 4) A bug that prevented 486 & Cyrix machines from factoring above 2^62 has been fixed. 5) The LockUserInfo feature no longer sends user info every time prime95 starts up. 6) A bug in setting minimized or maximized window in a shortcut to prime95 is fixed. 7) Test/Status now shows expected completion dates. New features in Version 16.3 of prime95.exe ------------------------------------------- 1) The LockUserInfo=1 setting is now sent to the server so that no member of a team can accidentally transfer the credit for work previously performed by the team. New features in Version 16.2 of prime95.exe ------------------------------------------- 1) Bug in calculating estimated time to factor a number has been fixed. New features in Version 16.1 of prime95.exe ------------------------------------------- 1) Prime95 can now test exponents up to 20.5 million. 2) Prime95 can now find factors up to 2^64. 3) The program now reports to the PrimeNet server new completion dates every 28 days (actually user adjustable from 1 to 60 days). This will improve the reclaiming of exponents that are not being actively tested. 4) The program now reports the current iteration number to the server for more informative status reports. 5) Intermediate files are now less likely to fail. If an error occurs during the writing of an intermediate file, the program continues on trying to write the intermediate file every 10 minutes. 6) A bug in the rolling average code has been fixed. Prime95 now modifies the rolling average when factoring too. 7) The prime.log file is now limited in size to 256K bytes. 8) The user information dialog box now has a checkbox to tell the server not to send email. 9) Setting LockUserInfo=1 in prime.ini will make the user information dialog box inaccessible. 10) Trying to run a second copy of prime95 will now start the already running copy of prime95. This makes the Hide Icon feature a bit more useful. New features in Version 15.4 of prime95.exe ------------------------------------------- 1) Quit GIMPS choice moved to the Advanced Menu (so novice users do not confuse it with exit). 2) A bug in httpnet.dll was fixed. It now works for even more proxy servers and firewalls. New features in Version 15.3 of prime95.exe ------------------------------------------- 1) More errors in detecting whether you are connected to the Internet have been fixed. 2) Minor bugs fixed. New features in Version 15.2 of prime95.exe ------------------------------------------- 1) A new primenet.dll that uses HTTP to communicate with the server is available. This should allow prime95 to work in environments that have firewalls installed. 2) An option that allows you to write a progress line to the results file every N iterations is available. 3) A dialog box lets you tell prime95 when you go on vacation. This will prevent the server from reassigning your exponents when you're on an extended vacation. 4) Some errors in detecting whether you are connected to the Internet have been fixed. 5) An option for you to initiate all contact with the Primenet server is now available (in case I didn't find all the problems mentioned in number 4 above!) 6) Support for Windows 95 services has been added. 7) To get Windows 95 service support to work, prime95 now changes its working directory to the same directory that prime95.exe is located. If you must run prime95 from a different directory than the rest of the files, then use new -W switch. New features in Version 15.1 of prime95.exe ------------------------------------------- 1) Better support for dial-up users to the Internet. 2) Prime95 no longer contacts the PrimeNet server at startup. 3) Prime95 will no longer let you select Pentium Pro or Pentium CPU type unless your CPU supports the process-specific instructions. 4) Bug where AMD-K6s were using the Pentium Pro factoring code (and crashing because of it) is fixed. New features in Version 15.0 of prime95.exe ------------------------------------------- 1) Prime95 can now contact a central server to get exponents to test, report results, and change your email address. No database is required! The old manual reservation system is still supported. This has led to a major reworking of the user interface. See the readme file for more details. 2) The Pentium factoring code (up to 60 bit factors) is about 4.5% faster. 3) You can now change how often prime95 saves intermediate files to disk. 4) You can now select one save file or two. 5) The auto-continue option is gone. The program now does an auto-continue by default. 6) -Q switch removed. The preferences dialog box lets you select whether the program should be quiet if a new Mersenne prime is found. 7) -H switch removed. Use the Hide Icon menu choice instead. 8) -P switch removed. The advanced menu now has a dialog box that lets you change the priority. 9) -A switch added. This allows you to run multiple copies of prime95 from the same directory. This is useful on multi-processor machines. 10) Prime95 no longer uses a prime95.ini file in the Windows directory. All information is kept in 3 local ini files: prime.ini, local.ini, and worktodo.ini. Eventually, all ports to other operating systems will use these same ini files. 11) The CPU dialog box now has an entry for the AMD K6 and an entry for how many hours per day you expect to be running the program. 12) The time estimate in the Status dialog box now takes into account the time you've invested in the current Lucas-Lehmer test. It also takes into account how many hours per day you are running the program. It also adjusts its time estimate if your computer seems to be running faster or slower than expected. 13) Timestamps in the results.txt file. 14) The results file is now named results.txt, not results. New features in Version 14.3 of prime95.exe ------------------------------------------- 1) The Pentium Pro factoring code is nearly twice as fast compared to version 14.2. New features in Version 14.2 of prime95.exe ------------------------------------------- 1) Corrected floating point round-off bugs in the factoring code that affected testing factors larger than 2^59. 2) The Pentium factoring code is 5-10% faster. 3) When an error is detected the program now waits 5 minutes before restarting from the last save file. 4) The detection of corrupt save files has improved. 5) The Advanced/Time feature now displays the estimated time to test an exponent. New features in Version 14.1 of prime95.exe ------------------------------------------- 1) The Pentium factoring code is 5% faster. New features in Version 14.0 of prime95.exe ------------------------------------------- 1) The program can now check exponents up to 5.26 million! To test these big exponents, you will need a new database and great patience. 2) The per-iteration error checking code has been improved. It will detect more errors and automatically restart from the previous save file. 3) Options/Tray Icon can be used to have prime95 occupy just a small part of the taskbar. 4) Options/No Icon can be used to have prime95 removed from the taskbar. Read the warnings in the readme file before using this feature. 5) Options/Preferences now has a checkbox to let you send results to a file called "results.txt" rather than "results". 6) Options/CPU now has a Cyrix checkbox. There is no Cyrix-specific code. This change provides better estimates in Range/Status. 7) Options/Torture Test runs a continuous Self Test. This is great for "burning in" a new machine. 8) The Round-off checking menu choice (which should be turned off) was moved to the Advanced menu. 9) The estimates in Range/Status have been changed slightly. Hopefully, these new estimate are a little more accurate. 10) The Options/Self Test option now takes nine hours. New features in Version 13.2 of prime95.exe ------------------------------------------- 1) Minor adjustments made to the per-iteration error checking code. It was occasionally raising a FATAL ERROR when it should not have been. New features in Version 13.1 of prime95.exe ------------------------------------------- 1) Faster! Prime now supports a wider variety of FFT run lengths. This means Lucas-Lehmer tests on exponents between 1.33M and 2.33M will be 13 to 40% faster. New features in Version 12.4 of prime95.exe ------------------------------------------- 1) A minor bug in the Pentium factoring code has been fixed. 2) When creating an intermediate file, instead of deleting the previous intermediate file it is renamed just in case there is a machine crash before the new intermediate file is written to disk. 3) Factoring is now 6% faster. 4) The program is now "network-enabled". See network.txt for more details. New features in Version 12.3 of prime95.exe ------------------------------------------- 1) The -h command line argument is now available. 2) Save files are generated every half-hour when factoring. New features in Version 12.2 of prime95.exe ------------------------------------------- 1) A minor bug in the factoring code has been fixed. New features in Version 12.1 of prime95.exe ------------------------------------------- 1) Command line arguments are now available to help you run the program on your co-worker's machines! New features in Version 12 of prime95.exe ----------------------------------------- 1) The program is faster! Expect to see improvements of 8 to 15%. The faster your CPU, the more improvement you should notice. The program also uses less memory. 2) There are now 5 separate hour-long self tests - one for each possible FFT length. You will run one of the new one-hour self tests even if you passed the self test in the previous version. 3) The program can now test exponents as high as 2,630,000! 4) The user interface has changed. a) You no longer enter a 3 or 4 digit range. Rather you enter an explicit starting and stopping point. For example, in the previous version you would enter 1234 for the range. In this version you enter a starting point of 1234000 and an ending point of 1234999. This makes it much easier to "check out" just part of a range. It also makes it easier to split a range among two or more machines. b) The "Only Find Factors" checkbox has been replaced. Use the Range / Factor menu choice instead. c) The Range / Double Check menu choice has been added for those of you who are double checking previously checked exponents. d) The Advanced / Password menu choice is now used to activate the rest of the Advanced menu. 5) The program now performs two new error checks every iteration! These will help guard against memory errors or "cosmic ray" errors. These new checks will not catch all such problems but should catch the vast majority. New features in Version 10 of prime95.exe ----------------------------------------- 1) The program will now undergo an hour long self-test before running any Lucas-Lehmer tests in your selected range. This self-test is also available from the menus. You might want to run this when you install new hardware or device drivers. 2) You can now get a status report on your range. Choose Range Status from the menus to get a report on the number of Mersenne numbers left to test, expected time to completion, etc. This information is also displayed whenever you choose a new range with Range Start or Range Next. 3) The File menu has been renamed Range - it seems clearer to beginners. 4) The Advanced menu has been disabled. You must read the readme.txt file to learn how to activate it. This is designed to keep novice users out of trouble. There is no reason, other than curiosity, for you to use any of the Advanced menu choices. 5) A bug in stopping and continuing when factoring in Version 8 has been fixed. New features in Version 8 of prime95.exe ---------------------------------------- 1) Factoring speed has been doubled for Pentiums. 486 machines will notice a 15% improvement when factoring. 2) The program will now automatically determine your CPU type and speed. This information is used in choosing the optimal factoring algorithm.