50 & 68 pin SCSI-2

From: Gary Hildebrand <ghldbrd_at_ccp.com>
Date: Sun Jun 9 12:50:57 2002

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
Received on Sun Jun 09 2002 - 12:50:57 BST