First post, by Stiletto
WinRAR was used to package these files at a 39% greater compression ratio than could be achieved using standard ZIP archiving. (1.31MB for ZIP vs. only 372KB for RAR)
WinRAR is by no means the "best". But it is surely one of the best popular ones.
Currently, 7-zip (http://www.7-zip.com) has obtained a level of popularity in the emulation world as a file rezipper. See also here:
ZipMax - http://www.clrmame.com/download.htm
AdvanceScan - http://advancemame.sourceforge.net/scan-readme.html
Some comments from the author of AdvanceScan:
Some months ago I did a lot of testing on the 7zip compression algorithm (called LZMA). […]
Some months ago I did a lot of testing on the 7zip compression algorithm (called LZMA).
The first thing discovered is that this algo is for sure better than all the others RAR, ACE, bzip2 (BWT), PPM, ... when recompressing roms.
The second thing is that you can't save a lot of space. Recompressing the whole romset you can save approximately only 550 MB respect the standard deflate implementation with maximum compression (pkzip, winzip, zlib).
And only 450 MB respect the 7zip deflate implementation.
These are the size of a complete romset with different compression :
zlib-deflate 4,606,494,475 bytes
7zip-deflate 4,503,914,469 bytes
7zip-lzma 4,026,339,475 bytes
See this thread:
http://sourceforge.net/mailarchive/forum.php? … 44&forum_id=718
And a few more comments from another MAMEDEV member regarding the security of MD5 and CRC32:
We use the checksum system to identify the ROMs, and we do that all the time. Since CRC32 is very easy to crack (defining crack as forcing a ROM to get any wanted CRC32 value by modifying 4 bytes), we have already seen people (lamers) modifying romsets, cracking the CRC so that it matches the original one, and distributing them. Raflsaiu is not a problem since we know
the correct ROMs don't exist, but if anybody did the same with some existing romsets, it would become impossible (read: very hard and painful) for us to identify which is the correct romset, since the _only_ automated thing we use is CRC.
Now, MD5 has been already cracked as well, no matter if the Unix/Linux world has adopted and advertised it for some reason. It might not be just as trivial as CRC, but there are known attacks to crack it. The only safe hash algorithm to date seems to be SHA-1, which I strongly suggest for MAME.
Sometime in the future, MAME will probably add SHA-1 as a file signature checking method. 😀
"I see a little silhouette-o of a man, Scaramouche, Scaramouche, will you
do the Fandango!" - Queen