Software Patents

· Patents

- Effects

+ Stac PPP ISDN

+ GIF, LZW

+ iPIX vs Dersch

+ Truetype

+ MSystems

+ ASF

+ GeoGrid

+ MBROLA

+ RSA & Co

+ BT Hyperlink

+ Rozmanith

+ OpenMarket

+ Altavista

+ XPointer

+ RDF

- Statistics

- Minefield

- Samples

· News

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Patents de Programari en Acció The LZW compression method is moderately ingenuous and moderately efficient. Better solutions are meanwhile available, some non-patented. But due to the inertia of de-facto standards such as GIF, ZIP, PDF etc, the LZW patent it is still causing a lot of grief. It is as if the conjugations of the English language had been patented.

European Commission wants Unlimited Patentability! Directive Draft by BSA

Unisys Web Site LZW license The license conditions of the patentee LPF on the GIF case Detailed Documentation Free Software developper forced to remove GIF support GIF support may not be included in free libraries. A developper reports about his difficulties with Unisys. Ghostscript EPO patent descriptions cannot be viewed, printed or manipulated under free Unix systems, because they contain LZW compression. The Acrobat Reader provides only a very incomplete and non-free replacement. It is tedious to view EPO patent descriptions with Acrobat, because they are organised as one PDF document per page. Concatenating pages can normally be done using imagemagick, but this program too can not handle the LZW compression because of patent problems. Xpdf: LZW patent problems with many PDF files The authors of a popular PDF viewer explain how the Unisys LZW patents are causing them trouble ZIP What about patents? gzip was developed as a replacement for compress because of the UNISYS and IBM patents covering the LZW algorithm used by compress. I have probably spent more time studying data compression patents than actually implementing data compression algorithms. I maintain a list of several hundred patents on lossless data compression algorithms, and I made sure that gzip isn't covered by any of them. In particular, the --fast option of gzip is not as fast it could, precisely to avoid a patented technique. The first version of the compression algorithm used by gzip appeared in zip 0.9, publicly released on July 11th 1991. So any patent granted after July 11th 1992 cannot threaten gzip because of the prior art, and I have checked all patents granted before this date. During my search, I found two interesting patents on a process which is mathematically impossible: compression of random data. This is somewhat equivalent to patents on perpetual motion machines. Check here for a short analysis of these two patents. One company CEO wrote to us about his troubles with the Unisys patent licensing conditions: I make a product called X which is a Y web server extension for dynamic image manipulation. I'd like to include GIF support in the product but its difficult to know how to do this effectively. The Unisys licensing restrictions are so severe that I wouldn't be able to offer a free trial version. Also I don't even see that I'm really responsible since I'm just providing a tool to enable others to put a solution together. It's a standard story.