Has there been experiments with 7zip for deb packages

[John Richard Moser]

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Lempil-Ziv-Welch has one patent left that I'm aware of, expiring August
11, 2006.  Its final patent is held by IBM.  I'm not sure if the LZW
patents apply to LZMA, as LZMA is I believe (like LZW) LZ78 based.

The Lempil-Ziv Modified Algorithm, LZMA, which 7z uses, is covered by no
patents that I'm aware of.  You could probably ask IBM if they have a
patent covering it implicitly because of LZW, and if you can use it if
so; what are they going to say?  They push linux like crazy.

Then the trick is ripping LZMA from 7z and seeing how well it works on
giant tarballs.  .7z and .tar.lzma should both be coded for if 7zip is
fully patent-free.  Then dpkg should be made to handle .7z and .lzma,
either by detecting the .deb or by .7deb/.deblz if you're so inclined.

I am not a lawyer.

Paul Sladen wrote:
> On Tue, 18 Jan 2005, Kristof Vansant wrote:
> 
> Hello Kristof,
> 
> 
>>Giuseppe from Mdk pointed me at: 7zip [..] which (apparently) gives a
>>20% size reduction on an OO.o source archive over bzip2 -
> 
> 
> It's something that probably warrants further investigation;  although I
> think people may have been avoiding it because of a patent issue in one of
> the algorithms it's using.  (I don't know more details).
> 
> I did see references to it in the ''Advanced Compressor'' in the cloop-utils
> suite used for building the LiveCD.
> 
> One of the reasons 7zip probably doing so well on OOo is because of the
> duplication in the XML files across languages being handled by the variable
> dictionary size (gzip==32kB, bzip2 == 965kB after block rearranging, 7zip ==
> unlimited) allowing it effectively to do the same as I experiemented with
> manually:
> 
>   http://www.ubuntulinux.org/wiki/HoaryHedgehogOpenOfficeL10nCompression
> 
> (I got a 33% ish saving when I last investigated.  However I think haggai
> said that OOo2 uses a different setup).  It might be interesting to see what
> can be archived with both techniques, but one of the things are the front of
> Ubuntu's mind is providing a Free distribution and such a fundamental tool
> can probably not be seen to have patent problems in any particular counties.
> 
> 	-Paul

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