Re: ramblings about old hardware, gzip, bz2, and pentium opts
On Tue, Nov 30, 1999 at 11:31:07AM +1100, Drake Diedrich wrote:
> On the bzip/gzip issue I think people should be aware that Andrew
> Tridgell has a plan to make gzipped data rsyncable, using relatively small
> gzip blocks divided by a rolling checksum (rather than a fixed blocklength).
[...]
> All packages would need to be recompressed to get the
> rolling blocks though.
> On implementing this capability:
>
> gzip would need to do the rolling blocks (not yet done).
I don't know exactly, if what rolling blocks mean, but perhaps you could
look at dict(un)zip, which is included in the dictd package. This is
from the beginning of the dictzip manpage:
DESCRIPTION
dictzip compresses files using the gzip(1) algorithm
(LZ77) in a manner which is completely compatible with the
gzip file format. An extension to the gzip file format
(Extra Field, described in 2.3.1.1 of RFC 1952) allows
extra data to be stored in the header of a compressed
file. Programs like gzip and zcat will ignore this extra
data. However, dictd(8), the DICT protocol dictionary
server will make use of this data to perform pseudo-random
access on the file.
Ingo
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