Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pacbell!att!occrsh!uokmax!blknowle From: blknowle@uokmax.UUCP (Bradford L Knowles) Newsgroups: comp.sys.mac Subject: Re: some (should-be) ground-rules f Message-ID: <1418@uokmax.UUCP> Date: 16 Jun 88 14:21:20 GMT References: <643@vsi1.UUCP> <76000213@uiucdcsp> <335@uva.UUCP> Reply-To: blknowle@uokmax.UUCP (Bradford L Knowles) Organization: University of Oklahoma, Norman, OK Lines: 37 In article <335@uva.UUCP> freek@uva.UUCP (Freek Wiedijk) writes: >In article <76000213@uiucdcsp> gillies@uiucdcsp.cs.uiuc.edu writes: >>But when I benchmarked compress on some digital pictures, I found that >>stuffit's LZW algorithm is much more efficient than compress's >>algorithm. I'm not sure compress is all that great a program. If you > >I thought that unsit used compress to decompress stuffit-files under unix. >That implies that stuffit and compress use the same LZW-compression, doesn't >it? > >-- >Freek Wiedijk UUCP: uunet!mcvax!uva!freek From what I understand, Raymond Lau looked at compress (which uses LZW only) and saw that it was a very good compression algorithm. But when he actually implimented it, he discovered that his compression ratios on MacPaint pictures was much lower than that of PackIt III (which uses Huffman encoding). He then decided to impliment the compression algorithms of both programs in his. That is why StuffIt is backwardly compatible with PackIt III, and also how it achieves such good compression ratios. BTW, StuffIt has an LZW only mode also, so it is basically compress for the Mac if you use it that way. As for unsit using compress, don't ask me, until five days ago, I had never even heard of unsit! In reality, I don't think it would use compress, even though they both use some form of LZW encoding. -Brad Knowles UUCP: ...!ihnp4!occrsh!uokmax!blknowle ARPA: blknowle@uokmax.ecn.uoknor.edu SNAIL: 1013 Mobile Circle Norman, OK 73071-2522 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Philosophy of Boris Yeltsin: "If one wants to be unemployed, one will criticize ones' boss. If one wants to be sent to Siberia, one will criticize the wife of ones' boss." -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Disclaimer: (The above opinions are my own. They have nothing to do with the Univeristy of Oklahoma nor intelligance of any sort. :-)