[vox-tech] gzip bug?

[Peter Jay Salzman]

hi kevin,

just out of curiosity, when you say it happens with all big files, how
big is big?  1k?  10k?  100k?  are youa bioinformatics dude?  ;-)  what
i'm getting at is -- are you dealing with files near the 2GB limit?

what happens when you try to do something like:

dd if=/dev/zero of=mybigfile count=10k
cp mybigfile myotherbigfile
gzip mybigfile
gzip -d mybigfile
diff mybigfile.gz myotherbigfile

change the 10k to whatever you need to reproduce the crc error.  also,
10k of /dev/zero should produce about a mp3 sized file (5 Megs).

if you can reproduce the CRC error this way, i totally encourage you to
write to bug-gzip@gnu.org.   gzip is one of the things that really ought
to be rock solid.  you can screw around with USB and TV tuner cards, but
gzip and bzip2 are our meat and potatoes.

btw, does this problem happen with bzip2?

also, when you gunzip these large files, how hard does your machine
thrash?  does the hard drive go like mad?

pete

begin Kevin Dawson <kdawson@ucdavis.edu> 
> Hi Pete,
> 
> Thank you for your suggestion. I'm using gzip 1.3 and gunzip 1.3 on a
> VFS file system. I'm having problems with practically all big files. The
> files are corrupted without ever leaving the Linux machine. For
> trouble-shooting with WinZip, I transferred some files to Windows using
> Samba.
> 
> The exact error message reads as:
> gunzip: MX.mat.gz: invalid compressed data--crc error
> 
> Your filter suggestion is great. It works, although, I'm still getting
> the error message:
> gzip: stdin: invalid compress data--crc error
> 
> Thank you,
> Kevin
> 
> 
> -----Original Message-----
> From: vox-tech-admin@lists.lugod.org
> [mailto:vox-tech-admin@lists.lugod.org] On Behalf Of Peter Jay Salzman
> Sent: Thursday, March 14, 2002 9:59 AM
> To: vox-tech@lists.lugod.org
> Subject: Re: [vox-tech] gzip bug?
> 
> hi kevin,
> 
> stream of consciousness:
> 
> are you saying ALL files on redhat can't be gunzipped?  or only
> particular files?  was this file transfered using windows ftp or http?
> perhaps it went through a NL/CR conversion?  faulty kermit transfer?
> where was the file created?  under a vfat system or under a VFS (linux)
> system?
> 
> try to use gzip as a filter:
> 
> gzip -d <myfile.gz >myfile
> 
> this will unzip as far as gzip can go before reaching the CRC error.
> it might recover some of your data.
> 
> also, can you post the exact error message (always a good thing to do
> when asking for help when something complains!)
> 
> can you post gzip's version number and mail me (not the list) a copy of
> the file you're trying to unzip?  i'll give it go here.
> 
> pete
> 
> 
> begin Kevin Dawson <kdawson@ucdavis.edu> 
> > Hi,
> > 
> > I cannot gunzip my gzipped files on RedHat 7.1. I get CRC error
> > messages. On the other hand, when the files are transferred to
> Windows,
> > WinZip opens them without any complain. Do you know any known bugs in
> > gzip or gunzip? Do you know another uncompressing utility on Linux
> which
> > does not invoke RedHat's gunzip to uncompress a .gz file.
> > 
> > Any suggestion is appreciated.
> > 
> > Kevin
> > 
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