[SunRescue] Tape help

[Joshua D. Boyd]

I've rescued a ArchiveST 4000DAT drive.  I hooked it up to my linux
machine.  The boo sequnce picks it up:

SCSI subsystem driver Revision: 1.00
scsi0 : QLogic ISP1020 SCSI on PCI bus 00 device 88 irq 17 MEM base
0xcc800000
  Vendor: ARCHIVE   Model: Python 28388-XXX  Rev: 4.98
  Type:   Sequential-Access                  ANSI SCSI revision: 02
Detected scsi tape st0 at scsi0, channel 0, id 5, lun 0
st: bufsize 32768, wrt 30720, max init. buffers 4, s/g segs 16.

At this point though, I'm not really sure what to do next, since I've
never used any sort of tape drive on any sort of unix before.  I gather
that I'm generally supposed to use tar and gzip to create a compressed
archive of what I want backed up, then I'm supposed to use dd to write it
to tape.  And somehow mt fits into the mix.  

Now, this is a DDS-2 drive (I think, some sources indicate that it is
DDS-90), but all I have are DDS-90 tapes (new in wrappers, except the two
I've opened already).  There are two lights on the front of the drive.
They are unlit by default.  When I put a tape in, one light turns a solid
green, and the other blinks orange.

I can't write .tar files to the tape using commands like dd if=some.tar
of=/dev/st0.  And using mt, mt -f /dev/st0 tell says mt: /dev/st0:
Input/output error.  the retension and erase command also return the same
error.  If I take the tape out, the tell command still returns the same
error, but the retension and erase commands return: mt: /dev/st0: No
medium found

Could someone please help me with this?  The guy I got it from thought it
was working, but he had no further use for it (had upgraded and was going
to chuck it).  Perhaps I was stupid to get used gear for my first tape
drive (well, I have some 150s around, but I've never used them), but I
take almost all old gear, and it is use this or don't do backups at all.

--
Joshua Boyd