Xref: news2.mv.net comp.os.msdos.djgpp:4128
From: Shawn Hargreaves <slh100 AT york DOT ac DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: DJP
Date: Tue, 21 May 1996 23:44:51 +0100
Organization: The University of York, UK
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On 21 May 1996, Vankeerberghen Pieter wrote:

> : Markus (the author of LZO1) sent me some notes, so the next release will
> : include some other stuff too (maybe an unpacker).
> 
> Aren't the Lempel ZIv codes patented by Unisys ?

There are a lot of variants of the basic LZ compression system. LZ 
compression basically just means finding repeated patterns of data and 
replacing later occurrences with a pointer to the first copy of the 
information, and there are thousands of ways to do this. LZW (the system 
used in .gif files) is patented by unisys, but there are plenty of other 
patent-free ways of getting the same results (eg. gzip).


/*
 *	Shawn Hargreaves.        Why is 'phonetic' spelt with a ph?
 *	Check out Allegro and FED on http://www.york.ac.uk/~slh100/
 */