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November 1999
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1999.12.01 00:08 "Re: libtiff 3.5.3 release.", by Michael L Welles
Richard Stallman informed Frank and I that the FSF's lawyers see LZW compression as encumbered by the patent: > My understanding is that LZW decompression is not encumbered by the LZW > patent, but that LZW compression is. Do you know if that is true? > > That is how our lawyers read the patent, and so that is what we > base our actions on. Tom Lane writes: > Izumi Ohzawa <izumi@pinoko.berkeley.edu> writes: > > Now, I need a solid reference that LZW decompression is not > > covered by the LZW patent. Nothing I have read, except for opinions > > or second-hand quotes at various forums, clearly indicates > > that decompression is not part of the patent. > > > Especially, does anyone have written views from the Unisys itself > > on this? > > Unisys' view is perfectly clear: they claim that decompression-only > software *is* covered by the patent. (They have a webpage giving their > version of reality at www.unisys.com, check there for an exact quote.) > > There are a number of qualified people who think that Unisys' > interpretation wouldn't hold up in court, and that a court would say > that decompression-only software isn't covered. But AFAIK there's > been no test case to find out. Do you want to be the test case? > > > Regardless of what court may or may not rule in the end, that > > doesn't matter. Most of us here, I think, just don't want to > > hear from Unisys counsels, ever. > > Yup. That's why I'm not shipping either LZW compression or > decompression code in libjpeg these days. It was a relatively painless > decision for me, because GIF-reading was never a critical part of > libjpeg, but I can see that dropping the LZW decompressor would be > crippling for libtiff :-(. Don't have any good advice... > > regards, tom lane > organizer, Independent JPEG Group > ------------------------------------------------------ M. L. Welles mike@onShore.com -------------------------------------------------------