SCSI disk/tape woes

Michael Thomas (mike@fasolt.mtcc.com)
Sat, 22 Feb 1997 13:04:57 -0800

I'm running 2.0.26 and just bought an HP SCSI
Surestor drive. The configuration I have is a
Buslogic 956 wide SCSI controller with one wide
drive (Quantum Atlas) and several other 8 bit
devices. The controller is setup correctly with
the high byte terminated, and the low byte left
alone.
When I originally installed the tape, I
boneheadedly used the CD ROM's SCSI slot (I didn't
have enough plugs on the ribbon cable), and
blythely went about backing stuff up until I
managed to torture a couple of my disks. After
I thought about it, I realized that the CD ROM
was what was terminating the low byte. Oops.
Anyhoo, I got a different ribbon cable, and the
low byte is terminated on the 8 bit bus, but I'm
still having some problems. What occurs to me is
that the other end of the bus (ie where the Atlas
is) isn't termintated at all. Am I missing
something here? The other end of the bus needs to
be terminated too. Do the newer fast/wide SCSI
drives all come with active termination these
days? I tried to figure it out from the Quantum
web site, but it wasn't especially helpful on that
particular question. On top of this, I'm having a
real difficult time finding 68 pin female
terminators.
If I'm totally out to lunch on the termination
issue, are there any known problems with the SCSI
tape support? I'm a little bit gun-shy about
running this until I resolve whether its a
hardware issue. FWIW, backing up to the tape
across the net (ie with the local disks basically
inactive) seems to not have any problems, implying
pretty strongly that it's a SCSI interation of
some kind (hw/sw).
Oh, one more thing: it seems that MTIOCTOP
MTCOMPRESSION is broken with the HP drive. Is
this a bug or a feature? Ie, is compression on
all the time on the tape drive, and you can't
change it, or is it the case that compression
is not supported in 2.0.26's st.c?

Mike, who also tracked down a
strange sense key the drive was
sending in some EOD situations --
it's sending ILLEGAL REQUEST.
Harmless, but odd.