What's New: New Features in Version 20.x of Prime95
NEW FEATURES IN VERSION 20.x of PRIME95.EXE
New Features in Version 20.6 of Prime95
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
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
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.
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.
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
Another fairly uncommon ECM bug was fixed. The bug caused "Factor does not
divide N!" errors.
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.
Prime95 no longer searches for a smaller factor when trial factoring discovers
a factor. The reasons are two-fold.
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.
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.
The undocumented AMPM feature controls how times are formatted in the Options/CPU
dialog box.
New features in Version 20.2 of Prime95
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.
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.
A bug in ECM testing was fixed.
New features in Version 20.1 of Prime95
A bug in the new GCD code was fixed.
Timings in the P-1 stage are no longer cumulative. There is a new feature
in undoc.txt for those that prefer cumulative timings.
Messages are now output prior to beginning the lengthy GCD.
The FactorOverride undocumented feature (not for use with PrimeNet) now supports
factoring to a deeper level than prime95 would ordinarily factor.
A bug where the worktodo.ini entry was not removed if P-1 found a factor was
fixed.
If P-1 finds a factor it now deletes any Lucas-Lehmer intermediate files.
A crash bug when continuing from a P-1 stage 2 save files with different available
memory parameters was fixed.
Resuming an LL test now outputs a line to the screen.
The Test/Status display now correctly calculates the estimated completion
time for an LL test when P-1 factoring is in progress.
Advanced/Factor menu choice was deleted.
A bug in computing P-1 stage 2 percentage complete was fixed.
New features in Version 20.0 of Prime95
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.
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.
Stage 1 of P-1 factoring is now faster.
The GCD used in P-1 and ECM factoring is now faster.
The Test/Manual Operation menu choice has been deleted.
The memory options in P-1 and ECM dialog boxes have been deleted.
The "send new completion dates" checkbox was moved from the Test/PrimeNet
dialog box to the Advanced/Manual Communication dialog box.
A bug in estimating time remaining for a factoring job was fixed.
AdvancedFactor now writes a line to the worktodo.ini - just like all the other
work types.
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.