Unix : how can I recover a corrupt tar file from a tape

Question

I've a tape contains a corrupt tar file. I'm using Unix SunOS 5.5.1. So when I run this command :

dd if=/dev/rmt/0 of=/tmp/outputfile.tar

I get this error message :

warning /pci@1f, 0/pci@1/pci@1/sunw, isptwo@4/st@4,0 (st4): Error for command : read Error Level: Fatal Requested Block : 11900 Error Block : 11900 Vendor : TANDBERG Serial Number: =:CREATED081 Sense Key: Media Error ASC: 0x11 (unrecorded read error), ASCQ: 0x1, FRU: 0x0

Please Help me I really need solution for this problem

Answer 1

Finally I solved my problem ^^' it was the bs format type :D Data was written in 512 so I did this :

dd if=/dev/rmt/0 of=/tmp/outputfile.tar bs=512 and all is fine :)))

Answer 2

The bad news is that the tape drive is reporting a media error.

Now this still can mean a few things:

1. Bad tape drive

   This is possible, but rather uncommon. To test it: check if it can read other tapes (it wrote itself), or read tapes other drives wrote.

2. Dirty heads

   Tape drives heads do need periodic cleaning. Esp if they are kept in less that spotless conditions this is very important. Cleaning tapes are commercially available, do match them with the right drive and do not overuse them either.

3. Mismatch between tape drive and tape medium

   Different tape formats (eg LTO) have generations (eg LTO-3), and there is a need for compatibility between the tape medium and the tape drive.

4. Bad tape

   Tapes do wear out, and need replacement to prevent that. Moreover a written tape has a limited shelf life just as well.

   In this last case, you might be able to find a commercial recovery service to try to do something, but I'd not bet the farm on the results ... And data recovery services are expensive ...