Author: F. Huber
Date: 08:05:10 12/06/05
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On December 06, 2005 at 10:33:14, Marc D wrote: >Hi > >I wonder if reducing Rybkas exe size with upx would result in strength loss >or higher nodes per second. > >I have shrinked the size down to 751 kb from original over 2,5 mb. > >So far it seems to work without problems but i have to do further testing. > >Besides that ,i don't know if it is allowed to compress the exe. >If anyone knows this matter please inform me. > >Best >Marc Hello Marc, all three answers to your questions are NO, i.e. there´s of course neither any strength loss nor any speedup (nps), because such a (UPX-)compressed EXE-file is simply de-compressed immediately when it´s started. After this de-compression the ´full´ engine is executed in memory, so there´s absolutely no difference while running (and of course de-compression only needs fractions of a second). Also I couldn´t think of any problem with compressing a program - otherwise even making ZIP-files would be illegal. ;-) But back again to compression with UPX: Why would you like to do this? Because of the 2.5 MB size? Is this really a problem nowadays with 100-300 GB harddisks? And there might be another problem with such UPX-files - I don´t know if it´s the case with the Rybka engine (probably not), but I remember that there has been a _big_ problem with an earlier UPX-compressed Arena-version: The original (uncompressed) version needed about 8-9MB RAM after the program has been started, but the UPX-compressed version used about 24-25MB! :-( It took some time until Martin Blume found out, that the problem actually was this UPX-compression - this de-compression seems to reserve RAM for all program resources whether being actually used or not (later while running). So he didn´t use UPX any longer for Arena 1.1. As I said, I´m not sure if this would be the case for Rybka (you could test it with any RAM-manager), but I really don´t see any advantages. Conclusion (in German): laß besser die Finger davon! ;-) Regards, Franz.
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