Ok, I'm assuming you're using the DI30, based on previous messages. The modules you need are OSST and IDE-SCSI. the device should be recognized as /dev/osst0
(unless you have more than one, but let's not get in to that.) make sure you are NOT running IDE-TAPE, b/c that does mess everything up. Once you have rmmod the IDE-TAPE and modprobe the IDE-SCSI and OSST, the device should be recognized and the mt commands should work. if nothing else you should be able to access the drive using tar. I don't know whether the site is still up, but check
www.linux1onstream.nl/test/README.osst -- this is probably the most indepth FAQ on the OSST driver out there.
Thanks,
Greg