From owner-cvs-all  Tue May 25 17:56:31 1999
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Date: Wed, 26 May 1999 02:56:21 +0200
From: Eivind Eklund <eivind@FreeBSD.org>
To: Robert Nordier <rnordier@nordier.com>
Cc: "Daniel C. Sobral" <dcs@newsguy.com>, cvs-all@FreeBSD.org,
	cvs-committers@FreeBSD.org
Subject: Re: cvs commit: src/sys/i386/boot/biosboot table.c
Message-ID: <19990526025621.I22354@bitbox.follo.net>
References: <374B1422.79F6707@newsguy.com> <199905252223.AAA17260@ceia.nordier.com>
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In-Reply-To: <199905252223.AAA17260@ceia.nordier.com>; from Robert Nordier on Wed, May 26, 1999 at 12:23:00AM +0200
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On Wed, May 26, 1999 at 12:23:00AM +0200, Robert Nordier wrote:
> Daniel C. Sobral wrote:
> 
> > Robert Nordier wrote:
> > > 
> > > I'm just not up on the legal side of things: how does "Adaptive
> > > Huffman Coding" stand in the patent world?
> > 
> > Interestingly, that's my concern too. Huffman encoding is poor
> > though. It is used to pre or post-compress a dictionary algorithm in
> > almost any decent compression algorithm. The exception (which I
> > think is used by bzip) requires too much memory to uncompress.
> 
> He calls it "Adaptive Huffman", though I think the emphasis is
> strongly on the "adaptive" part.

<DISCLAIMER: I last messed around much with this stuff in 1988/1989,
and everybody knows I am not a lawyer and wouldn't be an american
lawyer no matter what>

lharc uses a Lempel-Ziv-77 compressor with an adaptive huffman
encoder.

Huffman codes are from the 50s; if they ever were patented (and I
don't think they were), it would be expired.

LZ77 is from 1977; I am pretty sure this was never patented, and if it
was, it would be expired around now.  I believe the only LZ function
patented was Welch' (sp?) Lempel-Ziv-Welch compression (which is a
really beatuiful concept, as opposed to LZ77/LZ78, which are obvious).

Eivind.


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