Backup software

[jbk]

I need help to access the data I've written to /dev/nht0.

The  basic format the data is written to tape is:

TAPEDEV=/dev/nht0
WRT_TAPE="dd of=$TAPEDEV obs=126b

case
blah)
 LocalTar) if [ $level = F ] ; then
     tar zcf - $3 | $WRT_TAPE
    else
     tar zcf - -N \"7 days ago\" $3 | $WRT_TAPE
    fi;;
esac
#######################
This is an excerpt form the backup script I've modified for
my system.

I can use the mt command to move to the separate volumes on
the tape:
mt -f /dev/nht0 rewind
mt -f /dev/nht0 fsf 3

and I would think that:

dd if=/dev/nht0 of=/var/tmp/tape3/tape.tgz ibs=126b

would copy volume 3 to tape.tgz, but dd does not even access
the tape device but proceeds to write gibberish to tape.tgz
to the total of tens of MB.

This was a virgin tape with no previous data on it and it
was written to when I ran the script.

When I used the restore command with the -f /dev/nht0 option
I got the error mssg: 'this is not a dump tape' which is
what I half expected since I did not use dump to write the
tape. I have read the 'dd' and 'tar' info files.

Any hints would be helpful

with eyes glazed
    Jim Kelly-Rand