Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!whuxl!whuxlm!akgua!gatech!seismo!utah-cs!utah-gr!thomas From: thomas@utah-gr.UUCP Newsgroups: net.micro.mac Subject: Re: Re: Shrink To Fit (STF) Mac data compression. Message-ID: <1686@utah-gr.UUCP> Date: Wed, 19-Feb-86 12:10:47 EST Article-I.D.: utah-gr.1686 Posted: Wed Feb 19 12:10:47 1986 Date-Received: Fri, 21-Feb-86 07:09:51 EST References: <678@aicchi.UUCP> <736@astrovax.UUCP> <308@rosevax.UUCP> Reply-To: thomas@utah-gr.UUCP (Spencer W. Thomas) Distribution: net Organization: University of Utah, Salt Lake City Lines: 45 In article <308@rosevax.UUCP> hogan@rosevax.UUCP (Andy Hogan) writes: > * use "compress" on binhex'd files before posting and "uncompress" > after recieving. > > * incorporate a compress-style packing algorithm in a new version > of binhex. The first is not a good idea, because compressed files use all 8 bits of each byte, and are therfore not mailable. uuencoding them to mail makes a file almost as big as the original binhex. The 30% you see from compress is basically the difference between a file full of printing characters and one full of 8 bit characters. Further evidence is that the compressed binhex file is about the same size as the original binary! Here is an example, based on a binhex file I just happened to have sitting around: size file 0 RamStart.data These three are the original file 128 RamStart.info 25804 RamStart.rsrc 35104 ramstart The BinHex 4.0 version (with mail headers) 23689 ramstart.Z Compressed version of above 32672 ram.uu uuencoded version of above. It would appear that the compression algorithm in BinHex 4.0 could be improved on somewhat, but that might make it run slower (compress isn't exactly a speed daemon). The results above were obtained using a 16 bit version of compress (that uses several megabytes of memory). A smaller version, suitable for executing on a skinny mac would use 12 bits for compression, yielding a result not as good. 27543 .i/ramstart.12.Z BinHex compressed with bits=12 Applying compress to the binary and the uuencoding gives a better result than BinHex for this program, though: 19698 RamStart.rsrc.Z Rsrc file compressed with bits=12 27172 RamStart.uu Uuencoded version. 35104 ramstart The BinHex 4.0 version (with mail headers) Anybody want to build the compress algorithm into BinHex (making binhex 6.0?) -- =Spencer ({ihnp4,decvax}!utah-cs!thomas, thomas@utah-cs.ARPA)