From: Alexander Lehmann <lehmann AT mathematik DOT th-darmstadt DOT de>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Smaller distribution archives
Date: 13 Nov 1996 13:02:40 GMT
Organization: Technische Hochschule Darmstadt
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Message-ID: <56cgtg$eh3@rs18.hrz.th-darmstadt.de>
References: <199611120957 DOT WAA22298 AT papaioea DOT manawatu DOT gen DOT nz> <56afp6$4kv AT top DOT mitre DOT org>
NNTP-Posting-Host: fb0404.mathematik.th-darmstadt.de
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Michael F Brenner <mfb AT mbunix DOT mitre DOT org> wrote:
: "Malcolm Taylor" <malcolm AT manawatu DOT gen DOT nz> wrote:
: > What should I call it? [the new free archiver that is 2.5 times as
: > compressed as PKZIP?

: A critical question is whether the compression technology is truly free    
: software, and whether it is truly original. If the compression technology
: is a copy of stuff that is restricted by law in certain countries, then
: the product is not as useful as truly free software. Conversely, if it is
: truly original, then be sure to publish an immediatel paper showing the
: new compression methodology and name that compression method after 
: yourself. For myself, I have some very large un*x and DOS directory
: trees to test it on when you post it. Good luck in this application. 

Well, odds are that someone has already patented bits that are
necessary for basically any compressor. The ingenious thing behind
Info-ZIP was that they wrote a compatible code that doesn't touch the
patents PK had applied for and is very portable (and stable, I already
had PKZIP files that pkunzip didn't decompress correctly but unzip
did).

Any `new-generation' compression is likely to use arithmetic coding,
which is covered by loads of patents (which is not a problem for
commercial programs since they can just license, but a big problem for
freeware (as the GIF example should show)). Just adding a solid
archive option to a LZH type compression algorithm may improve the
compression quite a bit, but also makes the archives more difficult to
handle since they cannot be appended or updated without decompressing
and compressing the complete archive (and .tar.gz is already
established, at least in the unix, so nobody will want to switch).


bye, Alexander

-- 
Alexander Lehmann,                                  |  "On the Internet,
alex AT hal DOT rhein-main DOT de  (MIME, NeXT)                |   nobody knows
lehmann AT mathematik DOT th-darmstadt DOT de (MIME)           |   you're a dog."
<URL:http://home.pages.de/~lehmann/>