robjung@world.std.com (Robert K Jung) (04/25/91)
In reference to a posting concerning avoiding ARJ like the plague, let me clarify the patent issue. The ARJ 2.00 compression mechanism has been designed to be compatible with a myriad of LZ77 sliding window compressors. Therefore, it is entirely possible to build an archiver completely compatible with the ARJ format without coming within MILES of the ARJ 2.00 mechanism. In fact, that is what ARJ 1.10 is. ARJ 1.10 uses the public domain compressor in AR002. And it is completely compatible with ARJ archives. There is NOTHING in UNARJ that is proprietary to me. It is just a good decompressor. Unlike UNIX COMPRESS which uses a patented compressor and a patented decompressor, the UNARJ decompressor is not patentable as far as I can tell. The patentable mechanism in LZ77 mechanisms usually involves the string searching mechanism. This mechanism usually does not affect the decompression operation. ARJ 2.00 is just a slightly faster way to do LZ77 windows. And I make no special claims to the ARJ archive format. I hope that the fact that you can build ARJ compatible archivers with public domain algorithms eases people's concerns about using the ARJ format. Sincerely, Robert K Jung (robjung@world.std.com)
brad@looking.on.ca (Brad Templeton) (04/25/91)
In article <1991Apr25.004117.20744@world.std.com> robjung@world.std.com (Robert K Jung) writes: >good decompressor. Unlike UNIX COMPRESS which uses a patented compressor >and a patented decompressor, the UNARJ decompressor is not patentable as Patented compressor, perhaps. The decompression algorithm is so simple that I think it wasn't even described in the paper. Is it in the patent? -- Brad Templeton, ClariNet Communications Corp. -- Waterloo, Ontario 519/884-7473
oz@yunexus.yorku.ca (Ozan Yigit) (04/25/91)
<see ref> robjung@world.std.com (Robert K Jung) writes: >The patentable mechanism in LZ77 mechanisms >usually involves the string searching mechanism. Oh, goody, are you now telling us you are trying to patent a longest string match algorithm? This is even worse!! oz
brad@looking.on.ca (Brad Templeton) (04/26/91)
Actually, there's a strange benefit to all these patents on specific compression methods. They seem to be encouraging lots of development of superior compression methods. Without the patents, there would be little incentive to make methods that are just a tiny bit better or a tiny bit faster. Now there is -- and the cumulative tiny bits add up. -- Brad Templeton, ClariNet Communications Corp. -- Waterloo, Ontario 519/884-7473