Path: utzoo!utgpu!watserv1!watmath!att!mcdchg!laidbak!ism.isc.com!uunet!overload!dillon From: dillon@overload.Berkeley.CA.US (Matthew Dillon) Newsgroups: comp.sys.amiga.tech Subject: Re: Compression device Message-ID: Date: 19 Oct 90 18:34:51 GMT References: <291@geocub.greco-prog.fr> <1990Oct15.120046.15007@ericsson.se> Lines: 32 In article phil@adam.adelaide.edu.au (Phil Kernick) writes: >In article <291@geocub.greco-prog.fr> anthes@geocub.greco-prog.fr (Franklin Anthes) writes: >- >-I'd really like to find an amiga device (comp:?) which would automatically >-compress/decompress any files stored on it. I don't think such a device would >-be able to handle direct access ( it could probably fake it though ). But >-it still would be a really usefull tool. > >Isn't this basically how an RLL hard-drive controller on an I*M works? >As I understand it, it run-length encodes the data to be put on the >hard drive before storing it, and decodes it when reading it off. > >This would mean slightly slower access times, but an increase in disk >capacity of about 50%. > >Phil. Uh, no. RLL is not a compression scheme. It is a GCR like encoding which takes advantage of the higher clock rate to use larger code groups without violating the media transition limits. There is no compression involved. RLL is to disk media as MODULATION is to a modem. -Matt -- Matthew Dillon dillon@Overload.Berkeley.CA.US 891 Regal Rd. uunet.uu.net!overload!dillon Berkeley, Ca. 94708 USA