We bought a second hand tape drive for our backup HP server. The first time we used the tape drive was to copy valid data from the tape to the server. It seemed to work, as when I check the data on the server is looked ok. I reissued the tar -xvf command to try it again to make sure, and from then on the tape drive is 'busy' and the data on the backup server is corrupted now.
We have cleaned the tape drive twice. After either cleaning the tape drive or shutting down the server and restarting it, if I issue the command
mt -f /dev/st0 status
I get back
drive type = Generic SCSI-2 tape
drive status = 1107296256
sense key error = 0
residue count = 0
file number = 0
block number = 0
Tape block size 0 bytes. Density code 0x42 (unknown).
Soft error count since last status=0
General status bits on (41010000):

but no "BOT ONLINE IM_REP_EN" and I have to abort my session and relogon. When I type in
mt -f /dev/st0 status or mt -f /dev/st0 rewind
I get
mt: /dev/st0: Device or resource busy

If I try to
tar -xvf /dev/st0
I get
tar /dev/st0: cannot open: device or resource busy
tar error is not recoverable; exiting now

Welcome to LinuxQuestions.

What is the make/model of your tape drive? Is there a status light on the drive that indicates when the tape is "on line"?

The tape drive is a HP Storage Works Ultrium 448. The green light is on for 'ready' and when it reads the tape it flashes green on the "ready". We have just had the HP tech out and he put in a new drive from them, and now the tape drive flashes orange on the 'clean' and 'tape' and 'drive', and obviously we still can't access the
tape drive, so they are back tomorrow. They don't know. Very frustrating.

I was hoping someone might have had similar problems and found solutions.