[plug] SCSI tape drive disappearance

[Ryan]

Hi Plug,

Would anyone have any clue why my HP Dat40i DDS-4 SCSI tape drive either
vanishes or refuses to work after a week or so of uptime on one of my
servers?  

If I reboot it comes back and all is well in the world until a few days
later.  It still goes hiding whether I use the drive after a reboot or
not.

The errors range from basic I/O errors while writing to it all the way
to 'device not found' errors on /dev/st0 and nst0 - nothing appears in
dmesg or any logs - put console errors reported by tar or mt.

It is an old IBM PC Server 330 and works flawlessly for hundreds of days
at a time in all other respects.  It is running Debian Smorgasbord and
2.4.22

I noticed the errors firstly while I was learning about tape blocks etc
and playing with mt asf commands and the like on nst0 - did I offend it
somehow?

Short of it being a dodgy drive, is there anything else I might poke at
for an answer?

Thanks,

Ryan