#A4091 Controller
10-Jun-93 22:17:48
Sb: #103457-#A4091 Controller
Fm: John Gager 71336,624
To: Paul Wright 74135,1044
Well I did some checking today on the external SCSI-II connector
and hopefully will have that problem resolved. I ordered a high
density DB-50 to standard SCSI-50 cable. Since I'm building a tower
case for all my external drives, this should work out. Actually, it
wouldn't be too hard to make a DB-50 SCSI-II to DB-25 SCSI adapter if
I could just get my hands on the high density DB-50 connector.
Which brings me to a question for you SCSI guru's. While looking at
the pinout for the DB-50 external connector on the 4091, something
doesn't seem right. If it is truly SCSI-II then shouldn't it have
more than a 8-bit data bus, like 16 or 32? Here is the pinout and
maybe you can see what I'm talking about:
Pin's 1-25 are ground with except for pin's 12 & 14 reserved, and
pin 13 open. Pins 26-33 are /DB0-DB7, and then the rest are other
SCSI command and handshaking lines. The only data path is DB0-DB7.
Now I don't know that much about the SCSI-II spec, but it sure looks
like regular SCSI to me. Which brings another question of why they
used a DB-50 external connector if it is just regular SCSI specs?
Maybe it's a misprint in the manual, but if it isn't, then I would
like to hear from someone on how they are managing SCSI-II with such
an arrangement.