Is there a utility to scan tapes?

Is there a utility to scan tapes?

Post by Mike Moh » Fri, 18 Apr 1997 04:00:00



I had an incident a short while back where I received a tape that did
not match the documentation.  After several expensive phone calls, I
finally discovered the correct format and was able to read the tape.
Does anyone know of a tape to examine an unknown tape and guesstimate
its format?

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Is there a utility to scan tapes?

Post by Andrew Giert » Fri, 18 Apr 1997 04:00:00


 Mike> I had an incident a short while back where I received a tape that did
 Mike> not match the documentation.  After several expensive phone calls, I
 Mike> finally discovered the correct format and was able to read the tape.
 Mike> Does anyone know of a tape to examine an unknown tape and guesstimate
 Mike> its format?

I wrote a utility (shell script + a tiny piece of C code) to do this a while
back, but I no longer have it (though I might be able to recover it if there
is sufficient demand).

The basic idea I used (which you can easily do manually) was to use dd to
grab a single block off the tape, something like

# dd if=/dev/tape of=/tmp/blah bs=256k count=1

If the tape has variable block sizes this will read only one block, thus
revealing the block size the tape was written at. (Drivers in fixed block
mode will just read the first 256k). Then use file(1) to determine whether
the tape is tar,cpio or whatever.

Some formats (like HP-UX fbackup(1m)) are harder; what my utility actually
did was to skip to the next filemark after doing the above read, then try
and figure out the type of mark (I was using DDS tapes at the time). It
used this approach to list every volume on the tape, so fbackup tapes were
recognizable from the collection of small volumes at the start.

--
Andrew.

 
 
 

1. tape scanning sw for 8mm exabyte tapes?

Hi,

I used to work on a machine that had a utility called tcopy. It would
copy from one tape to another, but even better, if given only one
tape, would scan it and tell you how many files and what size, and
what blocksize. I really need this!

I'm working on an Iris (IRIX 4.0.4) and on a new HP 730 (with the
latest HP Unix) and neither of these machines seem to have this
utility. Is there a free one I can get anywhere?

Thanks.
--

 (301) 286-2396                          fax: (301) 286-1754

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