12 Sep
2016
12 Sep
'16
3:05 p.m.
On 12/09/2016 16:12, Douglas Taylor wrote:
I have a pair of 4mm DDS tapes from 1999 that I would
like to recover.
I was able to read one with tar on a Debian (jessie) Linux system, but
the second gives an error.
The second tape is a 3M brand with DDS markings and 4
bars next to the
DDS logo. It also has 'Media Recognition System' and DD-90 written on
it. Here is the dialog and error:
root at T5400deb:/home/taylor/4mm_tar_1998# tar -xvf
/dev/st0
tar: /dev/st0: Cannot read: Input/output error
tar: At beginning of tape, quitting now
tar: Error is not recoverable: exiting now
(None of the config jumpers were installed for the
tape that I could
read) Is the 2nd tape just bad and can't be read? Or do I need a
slightly different tape drive?
It could be corrupt, or it could be byte-swapped, or it could have a
strange block size (especially a small one), or the heads might need
cleaned after reading the last tape, or it might not have any valid
data. Does the debian tape driver support byte-swapping? Or is there a
bs and non-bs version? You could try reading it with something like
dd if=/dev/rmt/tapedevice bs=20b conv=swab | tar tvf -
or whatever the debian tape device equivalent is. Does debian have some
equivalent to mt(1) to read/set the drive's blocksize and to move
forward and back along the tape?
Personally I hate DDS/DDS2/DDS3. I always had better luck with half
inch and even 8mm, and better still with DLT.
--
Pete
Pete Turnbull