Status: Read
Received: from [192.48.153.1] by phillip.cerious.com (NTMail 3.03.0017/7.aaxh) with ESMTP id pcrews for <pcrews@cerious.com>; Wed, 18 Nov 1998 09:39:00 -0500
Received: from cthulhu.engr.sgi.com (cthulhu.engr.sgi.com [192.26.80.2]) 
	by sgi.sgi.com (980327.SGI.8.8.8-aspam/980304.SGI-aspam:
       SGI does not authorize the use of its proprietary
       systems or networks for unsolicited or bulk email
       from the Internet.) 
	via ESMTP id GAA02319; Wed, 18 Nov 1998 06:33:25 -0800 (PST)
	mail_from (owner-tiff@sgi.engr.sgi.com)
Received: (from majordomo-owner@localhost)
	by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF)
	id GAA35473
	for tiff-list;
	Wed, 18 Nov 1998 06:13:22 -0800 (PST)
	mail_from (owner-tiff@sgi.sgi.com)
Received: from sgi.sgi.com (sgi.engr.sgi.com [192.26.80.37])
	by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF)
	via ESMTP id GAA13212
	for <tiff-relay@engr.sgi.com>;
	Wed, 18 Nov 1998 06:13:21 -0800 (PST)
	mail_from (owner-tiff@sgi.sgi.com)
Received: from ligarius-fe0.ultra.net (ligarius-fe0.ultra.net [146.115.8.189]) 
	by sgi.sgi.com (980327.SGI.8.8.8-aspam/980304.SGI-aspam:
       SGI does not authorize the use of its proprietary
       systems or networks for unsolicited or bulk email
       from the Internet.) 
	via ESMTP id GAA09269
	for <tiff@sgi.com>; Wed, 18 Nov 1998 06:13:20 -0800 (PST)
	mail_from (palo@snowbnd.com)
Received: from jim-mail (d201.dial-4.cmb.ma.ultra.net [209.6.67.201]) by ligarius-fe0.ultra.net (8.8.8/ult.n20340) with SMTP id JAA24451; Wed, 18 Nov 1998 09:13:12 -0500 (EST)
Message-Id: <199811181413.JAA24451@ligarius-fe0.ultra.net>
X-Sender: web731dd@snowbnd.com
X-Mailer: QUALCOMM Windows Eudora Pro Version 4.0
Date: Wed, 18 Nov 1998 08:50:25 -0500
To: larry.jones@sdrc.com (Larry Jones),
        arybicki@interactivebusiness.com (Adam Rybicki)
From: James Palo <palo@snowbnd.com>
Subject: Re: lzw decompression.
Cc: ejs@bfd.com, doughill@grouplogic.com, tiff@sgi.com
In-Reply-To: <199811171650.LAA19448@thor.sdrc.com>
References: <3650F6F4.7EFADF39@interactivebusiness.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Sender: owner-tiff@fddi-sgi.sgi.com
Precedence: bulk

Some companies early on did try to take them to court and Unisys spent a
large sum to enforce the patent.  There is no justice , in the legal system
its who has the most money.  Most companies have just paid Unisys since it
was cheaper than fighting the patent.  For the record the patent states:


The compression of a serial character stream for transmission.

Which should not really apply to Gif or lzw reading of images.  But this is
a fight you will not win win Unisys.  Most companies have just not used the
lzw.

Lzw is not lz the w is Welch at Unisys added using a string table when
compressing.  There are a large number of patents on all sorts of variants of 
LZ, LZW and even the zlib compression is LZ77 which is supposed to be
patent free.  We do need a good lossless compression, but zlib used in the
PNG format is to complicated for general widespread use.

									Jim Palo

									Snowbound Software



At 11:50 AM 11/17/98 -0500, Larry Jones wrote:
>Adam Rybicki writes:
>> 
>> "Eric J. Schwertfeger" wrote:
>> > 
>> > The patent only covers compression, not decompression.
>> 
>> Sorry, but I don't think Unisys would agree with you:
>> http://corp2.unisys.com/LeadStory/lzwfaq.html
>
>It doesn't really matter whether Unisys agrees or not -- LZW
>decompression is *exactly* the same as LZ decompression, which is not
>patented.
>
>It's really too bad that Unisys can't make money any other way than by
>trying to extort license revenue out of an invalid patent.  It's also
>too bad that someone with deep pockets hasn't cared enough to take them
>to court and get it officially declared invalid.
>
>-Larry Jones
>
>Sheesh.  Who can fathom the feminine mind? -- Calvin
> 
Best regards
Jim Palo   <palo@snowbnd.com>
Snowbound Software tel: 617 630-9495  fax 617 630-0210
website:  http://www.snowbnd.com 
Imaging Software - Powerful, fast, reliable
