Message-ID: <01FD6EC775C6D4119CDF0090273F74A4FD6B15@emwatent02.meters.com.au>
From: "da Silva, Joe" <Joe DOT daSilva AT emailmetering DOT com>
To: "'support AT f-prot DOT com'" <support AT f-prot DOT com>,
   "'opendos'"
	 <opendos AT delorie DOT com>,
   "'zip-bugs AT lists DOT wku DOT edu'"
	 <zip-bugs AT lists DOT wku DOT edu>,
   "'arachne-development'"
	 <arachne-development AT arachne DOT cz>,
   "'gnu AT gnu DOT org'" <gnu AT gnu DOT org>
Subject: LZW patent expiry!   :-)
Date: Fri, 20 Jun 2003 18:55:50 +1000
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Reply-To: opendos AT delorie DOT com

Hi all,

I just thought you would be interested to know that, after today,
US patent 4,558,302 will have expired, since it will have exceeded
20 years from the date of filing (June 20, 1983) and it has already
exceeded 17 years since being granted (December 10, 1985).

As many of you will be aware, the original licensing terms for LZW
compression were reasonably generous, and so this compression
algorithm was adopted in many data file formats, including GIF,
ZIP (method 1) and PDF. Unfortunately, after this widespread
adoption, the patent holders (Unisys) changed the licensing terms,
making them arguably quite onerous (eg. see Reference #2).

While equivalent patents are still current in some countries (see
Reference #1), hopefully we will now see those applications that
have for years been deliberately "crippled" to avoid this patent
issue, soon restored to full functionality.  :-)

Best wishes,
Joe.

References :
1. http://www.unisys.com/about__unisys/lzw/index.htm
2. http://www.unisys.com/about__unisys/lzw/lzw__license__english.htm