On Tue, May 06, 2003 at 03:55:49PM -0500, C. Chan wrote:
> I eventually did something similar by running dd in a loop, and got back
> almost all of the 12GB of the tar archive except for a few bad blocks.
> I concatenated the pieces together into one file.
> 
> However the tar archive was compressed using gzip and trying to
> restore with tar stops at the first missing record:
> 
> gzip: stdin: invalid compressed data--crc error
> 
> gzip: stdin: invalid compressed data--length error
> Error 32 (Broken pipe) offset 630423552+32768, wrote 0
> amrestore: pipe reader has quit in middle of file.
> amrestore: skipping ahead to start of next file, please wait...
> tar: Unexpected EOF in archive
> tar: Error is not recoverable: exiting now
> 
> 
> Is there a way to recover from such an error in a gzip tar archive
> by using a binary editor to add fake data?

Many archive programs have options to skip over corruption to the start
of the next archived file.  I "think" gnutar has such an option but I
have not looked.

However most likely the problem is in uncompressing the file.  I am unaware
of anyway to resynchronize a gunzip after the corruption.  Without that
tar will not be able to do anything.

Perhaps you should seek a mailing list or netnewsgroup devoted to compression
and ask their members.

jon
-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
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