Compressing packages with bzip2 instead gzip?

Phillip Susi psusi at
Fri Jan 20 03:49:01 GMT 2006

Paul Sladen wrote:

>Incorrect.  A 'Zmap' is used, mapping uncompressed file-offsets to their
>position in the compressed stream.  If you need byte X then you download the
>compressed block from the previous restart marker to the next
>This is like on a hard-disk, if you need byte 813 you actually fetch the
>whole of the second sector (512bytes) on the hard-disk.
>By repacking the gzip you can add more restart-markers, lowing the
>compression ratio, but increasing the frequency and granularity of the
>restart-markers.  This makes the "sector size" smaller.

If I am now understanding it properly, this is NOT what the zsync look 
inside algorithm does.  I thought that is what it was doing, and that's 
why I was saying we don't want to do that: because it only works on 
files with gzip --rsyncable ( which stops and restarts compressing 
periodically ) and that lowers the compression, when we want to use 7zip 
to get better compression.  See my other post for my current 
understanding of the algorithm. 

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