Xref: utzoo comp.unix.ultrix:753 comp.sys.dec:1135
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!lll-winken!uunet!cbmvax!grr
From: grr@cbmvax.UUCP (George Robbins)
Newsgroups: comp.unix.ultrix,comp.sys.dec
Subject: Re: tar and Exabyte under Ultrix
Keywords: tar r, Exabyte 8mm, Ultrix
Message-ID: <6433@cbmvax.UUCP>
Date: 29 Mar 89 07:39:46 GMT
References: <416@seila.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 31

In article <416@seila.UUCP> don@seila.UUCP (Don Kossman) writes:
> we have an Exabyte 8mm cartridge drive, with the Q-bus...
> 
> we use it for dumps, which work just fine, and have used
> it with tar as well, but only with the "c" option (ie create
> a new archive).  when i use the tar "r" option (ie append to
> the end of the archive), however, i get an "error 0,
> writing to archive 1".  the exact same operation works just
> fine with my TK50 and TU81-plus...

The tar -r option probably requires that the device implement some
approximation of the traditional magnetic tape "skip" functions.
It is quite possible that this device can't emulate these function.

If you are trying to use a single tape over and over while appending
new data to the end of the prior archive, you may be SOL.  You might
be able to "read" to the end of the tar "file" and then write a
complete new archive, but operationally you'ed probably end up writing
over the wrong file a bit too often.

Hopefully, you write multiple tar archives to a single tape, simply
by using a "no-rewind" device name, as long as you don't have to
remove the tape from the unit.

How does it work otherwise?  I'm thinking about getting one of these
toys - multi-reel backups @6250 BPI are getting to be a pain.

-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)