py2exe and library.zip

[David Bolen]

Peter Hansen <peter at engcorp.com> writes:

> Good point.  When I wrote that I was picturing the form of compression
> that a .tar.gz file would have, not what is actually used inside a
> .zip file which is -- quite logically now that you point it out --
> done on a file-by-file basis.  (Clearly to do otherwise would risk
> your data and make changing compressed zips highly inefficient.)

Right, and yes, .tar.gz files are very problematic for such
algorithms, such as rsync.  In fact, there was a patch made available
for gzip (never made it ito the actual package I believe) that
permitted resetting the compression engine at selected block
boundaries - thus effectively bounding the "noise" generated by a
single change.  The output would grow a bit since resetting the engine
dropped overall efficiency, but you got a tremendous gain back in
terms of "rsyncability" of the file.

-- David