Since gif reading software must use an LZW decoder, is it legal? ---------------------------------------------------------------- After a bit of online investigation, I was sent the following letter:
From rms@santafe.edu Sun Sep 6 18:39:17 1998 Date: Sun, 6 Sep 1998 19:37:52 -0600 From: Richard Stallman <rms@santafe.edu> To: badger@prtr-13.ucsc.edu Subject: Re: Decoding LZW okay:: Source?
I am looking for someone who can explain why decoding LZW is not patented under either the IBM or the UniSys patents.
Because the wording of the claims that mention decompression describes a system which can do both compression and decompression.
This is evident in the words of the patent. I asked a lawyer to confirm that the words mean what they appear to mean; he said that they do.
(Note: in the past, Unisys has made statements that seem to imply they don't agree with this interpretation.)