Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!apple!portal!cup.portal.com!Henry_Burdett_Messenger
From: Henry_Burdett_Messenger@cup.portal.com
Newsgroups: comp.sys.atari.st
Subject: Re: BackupST a must have!!!
Message-ID: <36073@cup.portal.com>
Date: 19 Nov 90 19:17:49 GMT
References: <EbCeZYT0BwwuJF1FAS@transarc.com> <639@fsucs.UUCP>
  <2792@laura.UUCP> <fred.658682337@prisma> <2806@laura.UUCP>
Organization: The Portal System (TM)
Lines: 22

Compression should never, ever be used in backups. The idea of a
backup is to enhance data security by providing alternate copies of
data to be used the event of a failure or accidental deletion. 

Compression makes your backups less secure by increasing the
significance of each bit in the backup saveset. (e.g. if you lose one
bit in a compressed saveset, it is very likely that you will lose the
file that holds the bit; you may lose the whole saveset.) 

Most real backup systems for minicomputers or mainframes not only
don't compress, but they include redundant information to recover from
a media error. (VAX/VMS Backup XORs the blocks in a "redundancy group"
and stores that result; this allows single failures in a redundancy
group to be corrected.) 

Backups are no good if they fail when you need them!

Henry B. Messenger           STEVE   REICH   ^   THE   DESERT   MUSIC
henry_burdett_messenger@     MICHEAL  TILSON  THOMAS    ^   CONDUCTOR
   cup.portal.com            Steve Reich  and  Musicians  with Chorus
                             and members of the brooklyn philharmonic
                             text     ^     william  carlos  williams