GIF Gaffe — Our article on the recent Unisys/CompuServe GIF fiasco (see TidBITS-259) contained a few misstatements. First, Unisys’s patent on the LZW compression method was effective in 1985, not 1993 as stated in the article. Second, the TIFF file format is not itself licensed from Unisys, but the LZW method used in the TIFF format is licensed from Unisys.
Notwithstanding, the LZW compression format was first published in June of 1984, calling into question Unisys’s subsequent application for a patent on the method. Also, while CompuServe can be accused of many things, making a secret of LZW’s use in the GIF format is not one of them. It remains astounding that Unisys overlooked the (increasingly widespread) GIF file format for seven years.
CompuServe announced last week plans to serve as the coordinator of a new "free and open" GIF24 standard. GIF24 will support 24-bit, lossless compression and will presumably be free of proprietary technology. [GD]