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November 1999
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1999.12.01 16:04 "Re: libtiff 3.5.3 release.", by Michael L Welles
Not offhand, but their new position seems pretty clear: > Unisys has frequently been asked whether a Unisys license is required > in order to use LZW software obtained by downloading from the Internet > or from other sources. The answer is simple. In all cases, a written > license agreement or statement signed by an authorized Unisys > representative is required from Unisys for all use, sale or > distribution of any software (including so-called "freeware") and/or > hardware providing LZW conversion capability (for example, downloaded > software used for creating/displaying GIF images). (http://corp2.unisys.com/LeadStory/lzwfaq.html) I'd rather not be in violation by default. I'd prefer to make a patch or a branch distribution available for users who are licensed or are willing to take the risk. It's a pretty small change, and it'd be relatively easy to maintain. On a seperate note, gd (http://www.boutell.com/gd/), before switching to PNG, was shipping (as of 1.3) with LZW decompressor compatable run length encoding. I've grabbed the source and will be looking into adding this code as the default compressor. gd has a BSD-ish license, so the GPL "viral" effect shouldn't apply, though it's a little unclear: > Permission has been granted to copy and distribute gd in any context > without fee, including a commercial application, provided that this > notice is present in user-accessible supporting documentation. If the RLE code looks good, I might contact the authors (Hutchison Avenue Software Corporation) for their permission to distribute under the standard libtiff license. Bob Friesenhahn writes: > On Tue, 30 Nov 1999, Izumi Ohzawa wrote: > > Xpdf (PDF viewer) author goes to the trouble of not using LZW > > decompression in Xpdf itself, but exec's system's "uncompress" to > > do the decompression. I believe he must have been a target of > > "Unisys patent enforcement." > > I am not aware of any open source author being sued (or even > contacted) by Unisys regarding LZW in the sources. Removal of LZW in > the open source community was first driven by the philosophies of > Richard Stallman and the FSF and led to the creation of gzip, zlib, > and libpng. Most recently Unisys has expanded their demands on their > web site to mention open source software and web sites. This has > resulted in web sites switching to PNG, and additional open source > packages removing support for LZW compression. > > Does anyone know for a fact that an open source author has been > threatened by Unisys's laywers? > > Bob > ====================================== > Bob Friesenhahn > bfriesen@simple.dallas.tx.us > http://www.simplesystems.org/users/bfriesen > ------------------------------------------------------ M. L. Welles mike@onShore.com -------------------------------------------------------