Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!mailrus!ncar!husc6!m2c!applix!jim
From: jim@applix.UUCP (Jim Morton)
Newsgroups: comp.unix.xenix
Subject: Re: Xenix tar format
Summary: multi-volume tar
Message-ID: <815@applix.UUCP>
Date: 30 Sep 88 13:22:15 GMT
References: <14605@agate.BERKELEY.EDU> <421@marob.MASA.COM>
Organization: APPLiX Inc., Westboro MA
Lines: 25

> Tar has always choked on files which are larger than the backup volume.
> If there is a magical workaround for this, I wish someone would share it.
> 
> BTW, are there *any* copy/backup utilities besides `dump' which do
> allow files to span volumes ?
> 

Wait, what? As of Xenix 2.1, tar can span multiple volumes and split
files across them, and it works great! You can either do this using
the automatic defaults in /etc/default/tar, like:
	tar cv2 file1 file2 ... (for a DS/HD 96tpi floppy drive 0)
or by hand specifying the volume size and blocking factor, like:
	tar cvkbf 1200 20 /dev/fd096 file1 file2
the tar "e" option prevents any file from being split across a
volume. What tar won't do, and this would be my only complaint, is
if your doing a lot of small files and it hits the end of a volume
without splitting a file, when the user restores the floppies back
in, it won't prompt for a next volume - tar just completes and exits.
So you get some volumes where tar says "Insert next volume" and others
where tar just exits and the user has to type "tar xv..." all over again.

--
Jim Morton, APPLiX Inc., Westboro, MA
UUCP: ...harvard!m2c!applix!jim
      jim@applix.m2c.org