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FYI: LZW patent issues and libtiff, libjpeg

Today, Unisys' last patent worldwide on LZW expired --

"We were able to search the patent databases of the USA, Canada, Japan, and the European Union. The Unisys patent expired on 20 June 2003 in the USA, in Europe it expired on 18 June 2004, in Japan patent expired on 20 June 2004 and in Canada until 7 July 2004."

However, IBM was issued a patent *on the same algorithm* that is good for another two years. (The 'uniqueness' requirement of patents under US law probably means this patent is invalid, but I don't want to fight Big Blue's lawyers.)

So, cygwin's libtiff will *continue* to be distributed without LZW support -- until IBM's patent expires, is ruled invalid in a judicial proceeding, or they voluntarily and officially release it into the public domain(*).

Similarly, jpeg's arithmetic compression technique is covered by the IBM patent. The code is included in the libjpeg source, but is #ifdef'ed out, at present. (In its current form, libjpeg uses only Huffman encoding for compression). So, for the time being, the arithmetic compression code in libjpeg will remain #ifdef'ed out, in cygwin's libjpeg distribution.


(*) not very likely, IMO, given that they are using the patent in the SCO case:

SCO vs. IBM lawsuit, IBM's counterclaim #175 and #176:

175. IBM is the lawful owner, by assignment, of the entire right, title and interest in United States Patent No. 4814746 ("the '746 Patent"), duly and legally issued on March 21, 1989 to Miller et aI., entitled "Data Compression Method". A copy of the ' 746 Patent is attached hereto as Exhibit X.

176. Upon information and belief, SCO has infringed, contributorily infringed and/or actively induced others to infringe the '746 Patent within this judicial district and elsewhere in violation of35 U. C. 9271 by, without authority or license from IBM, (a) making, using, selling and/or offering to sell products, including Unix Ware and Open Server, that practice one or more claims of the '746 Patent and (b) actively, knowingly and intentionally causing and assisting others to infringe one or more claims of the' 746 Patent.

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