Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uunet!know!zaphod.mps.ohio-state.edu!van-bc!ubc-cs!alberta!atha!cbmvax!grr
From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.unix.ultrix
Subject: Re: HELP!!! Version 2
Keywords: tar
Message-ID: <14344@cbmvax.commodore.com>
Date: 11 Sep 90 05:06:13 GMT
References: <136@opus.NMSU.Edu>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA
Lines: 38

In article <136@opus.NMSU.Edu> bemery@nmsu.edu (Bryan Emery) writes:
> This is concerning my second attempt at backing up my user files before I
> attempted to install Ultrix 4.0.
> 
> I used the tar command as follows to create what I thought was one archive:
>   tar c /usr/users
> At the completion of that, I did:
>   tar r /usr2
>       which I understood to mean that those files would be 'added' to the
>       existing archive.

That's what it's supposed to mean, but it looks like you've been screwed over.

> Strange thing is, if I do:
>   cp /dev/nrmt0h backup.tar
> I get a file that is about 64 megabytes big.  When I then do:
>   tar tf backup.tar
> I only see maybe 10 files out of /usr/users.  However, if I do:
>   more backup.tar
> and move down through the file, I can "see" some of my filenames that I need
> to get.

There's no particular promise that cp will use the appropriate blocksize
to suck in the tape image.  Try using "dd if=/dev/nrmt0 bs=20b of=disk.file"
which will, then using "tar tf disk.file" and see if you get any better
results.

> Any suggestions???

If you get really desparart you can play with gnu tar, which may be a little
more flexible about recoving most of what appears as a corrupted tape.

Also, you neglect to mention what kind of tape you are using, is it DECish
or some third party device (Exabyte?) that doesn't backspace too well?
-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)