Richard Erlacher wrote:
You're right, of course, but it's also possible to configure your wide SCSI
devices to work on a narrow controller. I have that configuration working
with SCA devices, which make it somewhat easier (at least less costly) but
it's necessary that you consult the documentation for your wide drives to see
about configuration details. The drives (several types) that I have all allow
for "narrow" configuration with a single jumper. That's necessary, but
not
sufficient, since you also need the adapter cable, or an adapter board. If
you configure the drive for narrow transfers, I doubt it matters whether you
terminate the upper part of the bus appropriately, but if you have the option,
I'd terminate the upper bus anyway.
If you don't have an adapter and can't find one that's cheap enough, you
could
use one of the 3-way adapters that abound on the web for attaching SCA drives
to a WIDE controller or a Narrow controller. There are at least three types,
and what you want is the one that has BOTH the wide and narrow connectors.
You're not required to use the SCA connector, though that's how the boards are
intended to be used, and can then connect both a WIDE cable and a NARROW cable
to the board, presumably with the NARROW cable going to your controller. I've
done this with complete success, so you should have no trouble.
Dick
My Quantum drive could either be jumpered for narrow mode, or it would
automatically fall back to 8 bit bus width if it only saw 8 bit data.
AFAIK, SCA is just another variation on SCSI-3, and were primarily for
hot-swap drives. Personally, I don't belive in a daisychain of
adapters to get from connector A to connector B.
Out of curiosity, has anyone tried running both SCSI-3 and SCSI-2
devices on an Adaptec 2940UW card, using separate 50 & 68 pin cables?
I'd like to do that, but then I'd have another big ribbon cable taking
up room in my PC here.
Gary Hildebrand
St. Joseph, MO