<<This is a follow-up to my question of does anyone have non-HP FW SCSI
drives on a 3k. What models and how are they configured?  Thanks to those
on the list who have helped.

I paid HP to come and trouble-shoot.  At first they weren't a lot of help
since my drives are not HP drives.  They did it mainly to prove that
their controller card was OK.  However, I checked the FWD controller card
(28696A) and it is differential.  The fact that these drives are not
differential leads me to believe that is why they cannot be seen on this
controller card.>>


SE drives definitely will not work with differential adapters, and
vice-versa. In fact, this situation turns off the SCSI bus:
  "The DIFFSENS signal of the connector is used as an active high enable
for the differential drivers. If a single-ended device or terminator is
inadvertently connected, this signal is grounded, disabling the
differential drivers" (SCSI-2 Specification. 5.4.2)

And (contrary to my previous thinking) it appears that all "Fast/Wide"
SCSI devices HP uses in their mini-class hardware are differential. Which
is appropriate, since the SCSI-2 specification specifically recommends
against using SE interfaces to "Fast" (i.e. 10MHz) SCSI devices.

<<I don't think that configuration or distant has anything to do with it.
 You may want differential drive when you plan on long SCSI distances.
 However, I think that non-differential drives cannot be seen by the
controller card.>>


Definitely not.

<<HP brought a FWD drive and it worked fine.  It was recognized instantly
by MAPPER.

What threw me off is the fact that SEAGATE has both ST34371W and
ST34371WD model numbers.  They also have -WC and -DC drive suffixes.
IODFAULT lists the drive without the D.  In the single-ended SCSI world,
I don't think that differential drives comes into play.  In the Fast-Wide
SCSI world on the HP3000 I think differential drives are required.  I am
working with the SEAGATE vendor to trade the ST34371W drives for
ST34371WD drives.  I will see what happens when the new drives arrive.>>


Actually, the lack of the "D" is Seagate's "fault" not HP's; these drives
identify themselves to the SCSI adapter with no "D", whether they use a
differential interface or not. For example, I have 3 ST15150WDs on an
Adaptec AHA-2944W in my PC at home, and the boot-up SCSI-bus-poll shows
"ST15150W".

Steve