RS> The same INPUT file, sure, clearly not the same OUTPUT file
 RS> tho, the length was different. So the CRC should be different
 RS> too.

 FM> No. The CRC of a file within an archive is calculated on the
 FM> data in the original file, not the compressed file, for all of
 FM> the following: ARC, ARJ, LHARC, PAK, PKZIP, SQZ, ZOO and any
 FM> compatible programs.

  You've got him on toast with this one: an absoulute error in his
understanding of how it works. I sincerely hope you'll save the
original messages and hammer the little shit into the ground with it.

 RS> What was being discussed is if repeated rezipping of the SAME
 RS> file can produce DIFFERENT zip files, different lengths, but
 RS> with the SAME CRC. Its quite easy to see how repeated rezipping
 RS> can produce a differently compressed file, most obviously with
 RS> a different set of dictionary terms, but that WONT produce two
 RS> files with the SAME CRC.

 FM> Yes it will. See above.

  If you don't want to give him a kicking, give him to keith.

 RS> Sure, different say ram available could well produce that
 RS> result, BUT that is very unlikely to produce the SAME CRC.

 FM> From the same data it will, and that's what I think was
 FM> happening. The one byte change was a different problem.

 RS> Nope.

 FM> Yes.

  You've got him! He has no way out. keith will love it. I rather like
it myself.

Regards,
Bob
___ Blue Wave/QWK v2.12
@EOT:

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