Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!samsung!uunet!pdn!tscs!tct!chip From: chip@tct.uucp (Chip Salzenberg) Newsgroups: comp.unix.questions Subject: Re: Backups using compress Message-ID: <275A875A.3AB0@tct.uucp> Date: 3 Dec 90 17:11:53 GMT References: <14582@smoke.brl.mil> <27551FBF.2222@tct.uucp> <11389:Nov3010:16:4190@kramden.acf.nyu.edu> Organization: Teltronics/TCT, Sarasota, FL Lines: 24 According to brnstnd@kramden.acf.nyu.edu (Dan Bernstein): >In article <27551FBF.2222@tct.uucp> chip@tct.uucp (Chip Salzenberg) writes: >> I would think twice before using this method for backups. LZW >> compression (i.e. /usr/bin/compress), like most kinds of compression, >> is _extremely_ unforgiving of trashed data. If you lose ONE BYTE, the >> rest of the archive will probably be lost permanently. > >If you want to correct errors, use an error-correcting code. Sure, error correction is very nice. But sometimes data are lost, period, no recourse, from the *middle* of a backup. And in those cases, if you've compressed your archive, you're SOL: everthing from the point of failure to the end of the archive is gone forever. If you've compressed individual files, at least you can recover the files on the untrashed portions of the archive, both before and after the point of failure. >Sheesh. My word(s) exactly. -- Chip Salzenberg at Teltronics/TCT , "I'm really sorry I feel this need to insult some people..." -- John F. Haugh II (He thinks HE'S sorry?)