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From: thorinn@skinfaxe.diku.dk (Lars Henrik Mathiesen)
Newsgroups: alt.sources.d,comp.sources.d
Subject: Re: Unnecessary tar-compress-uuencodes
Message-ID: <1990Jul17.180459.974@diku.dk>
Date: 17 Jul 90 18:04:59 GMT
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drd@siia.mv.com (David Dick) writes:
>It has been reported that Unisys owns a patent on Zempel-Liv or 
>LZW compression (I don't remember which) and believes every current 
>use of compress is in violation!

I think I have seen the paper describing that work. It described the
use of some sort of Lempel-Ziv encoding between a mainframe and a disk
subsystem --- the processor being so fast that it could compress one
block while the previous was being transferred, thus increasing
throughput.
  A patent based on that would probably be a process patent covering
the use of a specific algorithm (12 bit compress) in a particular part
of the I/O path in a disk system. If UniSys think it covers the use of
a PD compress program on a general purpose computer system, either
they really got a patent for the algorithm (which they oughn't be able
to) or they have misunderstood something.
  On the other hand, I think the W in LZW may be the author of that
paper, which might give them a claim on that version of the algorithm.

>I think they are taking steps to deal with this.

I hope those steps don't work.

--
Lars Mathiesen, DIKU, U of Copenhagen, Denmark      [uunet!]mcsun!diku!thorinn
Institute of Datalogy -- we're scientists, not engineers.      thorinn@diku.dk