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Resources for “Compression Tools Compared”

Issue 137

From Issue #137
September 2005

Jul 21, 2005  By Kingsley G. Mor...
 in
Resources for the print article.

lzop: www.lzop.org

rzip: rzip.samba.org

lzma: martinus.geekisp.com/rublog.cgi/Projects/LZMA

p7zip and lzma: adn.diwi.org/debian

Various: sourceforge.net

SSH and scp: www.rpmseek.com

Canterbury Corpus: corpus.canterbury.ac.nz

Calgary Corpus: links.uwaterloo.ca/calgary.corpus.html

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rzip looked promising. I

Anonymous's picture
Submitted by Anonymous (not verified) on Tue, 12/06/2005 - 12:06.

rzip looked promising. I started hacking it a bit here and there mainly in main.c and in the stream.c and got rid of libbz in it so now I may use it as preprocessor before gzip.

I threw urandom data at this hacked variant and was not able to decompress what was compressed at -0 and -1 levels. Then i runned original rzip-2.0 against the same urandom data and it shows same bug.

So the hint is: Don't use version 2.0 (rzip.samba.org OR debian's 2.0-2) with compression levels -0 and -1 for anything inmportant before first checking if you can decompress. Other levels were fine with same data but I was not giving it any heavy testing.

Still it's able to cut in 10 minutes from 6538537833B of mail+spam down to 4466144683B at compression level 0 (these data decompresses cleanly) here and that is the hacked version without bzip2 - only rzip's own part. Yet the hacked variant without bzip at level -9 is terribly slow - but the system was swapping/trashing/mmaping(comparing large chunks of data) heavily

LZMA 0.03-1 source

Charles Hewson's picture
Submitted by Charles Hewson (not verified) on Sat, 08/06/2005 - 20:55.

If anyone finds working lzma please post the URL and/or email me. I have found 0.03 and 0.04 versions on sites above but neither works as documented in article. I have tried 2.4.26 & 2.6.11 kernels. The -x -s26 switches simply return the word "error" and do nothing. Without switches 0.03 encodes but will not decode. I never got 0.04 to encode.

Oops - Forgot to Include Source Location ..

Graham K Jenkins's picture
Submitted by Graham K Jenkins (not verified) on Mon, 09/05/2005 - 19:11.

The version I used was LZMA 4.27 on Fedora Core 4.

You can find it at: http://sourceforge.net/projects/sevenzip

Ciao ..

Working lzma

Graham K Jenkins's picture
Submitted by Graham K Jenkins (not verified) on Sun, 09/04/2005 - 17:55.

I have compiled and used it on Fedora Core, using both 32-bit Intel and 64-bit AMD machines.

Hope this helps.

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