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Path: utzoo!mnetor!seismo!ll-xn!cit-vax!mangler
From: mangler@cit-vax.Caltech.Edu (System Mangler)
Newsgroups: comp.unix.questions,comp.sources.wanted
Subject: Re: Backup Utilities for Unix
Message-ID: <2654@cit-vax.Caltech.Edu>
Date: Mon, 11-May-87 07:17:49 EDT
Article-I.D.: cit-vax.2654
Posted: Mon May 11 07:17:49 1987
Date-Received: Wed, 13-May-87 01:14:54 EDT
References: <1308@ci-dandelion.UUCP> <4360@videovax.Tek.COM> <1422@ho95e.ATT.COM> <353@mtxinu.UUCP>
Organization: California Institute of Technology
Lines: 16
Keywords: system management backups dump restore
Summary: 512/1K filesystem
Xref: mnetor comp.unix.questions:2247 comp.sources.wanted:1140

In article <353@mtxinu.UUCP>, ed@mtxinu.UUCP (Ed Gould) writes:
> Why USG decided to drop dump/restor from System III (or maybe it was
> still distributed with SysIII but discouraged), I'll never understand.

It was probably too much work to make restor work on a dual-blocksize
filesystem such as that found in Sys V.  Restor believes that disk and
tape data both come in units of BSIZE.	Getting it to convert 512-byte
tape records to 1024-byte disk blocks (or vice versa - take your pick)
is a *pain*.

Dump's speed is limited by the small blocksize of System V filesystems.
Volcopy can read in large chunks.  On the other hand, dump doesn't
waste time copying free blocks like volcopy does.  With slow tape drives
(or UN52 controllers), dump wins; with fast tape drives, volcopy wins.

Don Speck   speck@vlsi.caltech.edu  {seismo,rutgers,ames}!cit-vax!speck