SUMMARY: Determining what's on a tape.

From: Jeff Kennedy (
Date: Fri Jul 30 1999 - 19:11:55 CDT

There is a fairly simple method to discover what archive format is on a
tape; dd.

A majority suggested the following method (give or take a few minor

     dd if=/dev/rmt/0 of=/tmp/out bs=64k count=1

     file /tmp/out

This works exceedingly well for tar and cpio but not as clear cut for
ufsdump. But then again, if it's not tar or cpio, it's probably ufsdump.

Another suggestion made by a couple of people was to use tcopy to discover
the number of archives on a tape. Good idea but it doesn't seem to work
unless I've missed something. I tried it on a ufsdump tape that had 5
seperate dumps on it and it only returned a single file listing. It looks
like tcopy will go to the first eof that it finds and return.

Thanks to:

Pete Alleman Darren Dunham
Dan Stromberg Michael Wang
Colin Melville Brett Lymn
Stephen Harris Sean Wilcox
David Mitchell Mathew Stier
Stewart McLeod Danny Johnson

---------------------- Forwarded by Jeff Kennedy/NDS on 07/30/99 05:08 PM

"Jeff Kennedy" <> on 07/29/99 01:44:19 PM
 cc: (bcc: Jeff Kennedy/NDS)
 Subject: Determining what's on a tape.

I have a 4mm tape that was brought back from the archives and I would like
to know what it contains. Since I was not the one who archived it I have
no idea what format was used.

Is there a simple way of telling what exactly is on a tape (format not
content) without actually running through all the possible archive commands
to see which one works?



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