Compressing packages with bzip2 instead gzip?

John C. McCabe-Dansted gmatht at
Thu Jan 19 01:36:04 GMT 2006

On Thursday 19 January 2006 06:04, Phillip Susi wrote:
> > Zsync can be taught that restart points occur every 900kB, likewise zsync
> > could be taught to find the restart markers in LZMA, but there's even
> > less of those.  You have a choice of optimising for two cases:
> The data stream DOESN'T restart every 900 KB, that's the problem.
> That's what gzip --rsyncable does, and bzip2 and 7zip don't support that
> ( and don't want to since it sacrifices compression ).  When you do
> cause data restarts every x KB, zsync doesn't require any special
> handling to sync them efficiently, the restarts themselves contain the
> fallout from a small change in the original uncompressed stream, which
> means there is less changed data zsync has to find and send.

I don't think we could modify zsync to handle bzip2 effectively. There are 
likely to be small changes through out the tar file, so with a block 
compressor there would most likely be changes in every block, meaning that 
zsync would have to download every block.

John C. McCabe-Dansted
Masters Student

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