RE: [Bug-gnubg] Bug: 14 point one-sided race database withmakebearoff.exe

[Joachim Matussek]

Hello Ian,

well, that´s why i wrote which file systems i used.

NTFS and even FAT32 can handle much larger files than 2,1 GB.

http://www.microsoft.com/resources/documentation/Windows/XP/all/reskit/en-us/Default.asp?url=/resources/documentation/Windows/XP/all/reskit/en-us/prkc_fil_tdrn.asp

I realized that 2147483647 has something to do with 2^x. Especially this number 
is the limit of some integer types.

http://www.phim.unibe.ch/comp_doc/c_manual/C/CONCEPT/data_types.html


Joachim Matussek



"Ian Shaw" <address@hidden> schrieb am 06.01.05 10:51:08:
> 
> From: Øystein Johansen
> Sent: 05 January 2005 21:15
> 
> > Joachim Matussek wrote:
> > | Hello,
> > |
> > | i tried to create one-sided race databases with makebearoff.exe. At 
> > | first i created one for 13 points which worked well.
> > |
> > | Afterwards i tried 14 points but the program stopped when the temp 
> > | file reached a size of about 2,1 GB (2147483647 bytes). I 
> > tried under 
> > | Windows with NTFS as well as under Linux with FAT32. Error message 
> > | under Linux was "File size limit exceeded". I don´t 
> > remember the error  
> > | message under Windows but I think it was an internal message of the 
> > | .exe.
> > 
> > Hmmmmm.... this sounds familiar. Hasn't this been reported 
> > before? I may be wrong but wasn't it Morten Wang who reported 
> > this problem years ago?
> > Or maybe it was Ian?
> > 
> > If I remember correctly Ian (Shaw) and Morten are the two 
> > users who have built the biggest bearoff databases. Maybe one 
> > of them knows something?
> > 
> > Worst case we could make a limit of 13 point for the one 
> > sided database.
> > This would be a bad solution though since storeage of several 
> > Gigabytes is no problem anymore.
> > 
> 
> There is a limit on the file size that the PC file system can handle. It is 
> 2^31 bytes = 2147483647. I assume it's 2^31 instead of 2^32 because the 32nd 
> bit is used as the +/- sign.
> 
> Anyway, this puts a limit on the size of the database. 13 points works but 14 
> doesn't, as you have seen.
> 
> On a related note, I've been wondering if the two sided database could be 
> compressed by omitting gin positions, that is, positions where one side is 
> guaranteed a win but no gammon is possible. This out to have a greater and 
> greater effect as the size of the database increases, since you will have 
> more and more lop-sided positions.
> 
> -- Ian


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