Hello Managers,
I'm looking for some advice/experience with mixing differential
SCSI with non-differential.
We've got an AlphaStation 600 with a KZPSA-BB PCI board that has two
68 pin SCSI connectors on it. SCSI connector 1 is in the middle
of a ribbon cable, one side goes to the internal SCSI peripherals,
a SCSI disk, CD-ROM and terminates on the end of the cable, the other
side of the ribbon is connected to the rear panel with a 50 pin
micro-scsi connector and an external termination. But this latter section
of ribbon cable has the outer 9 wires on each side of the ribbon cable
cut off to give us 50 pin SCSI! This seems to indicate that non-differential
SCSI devices are supported on a differential controller, but I've had
mixed results.
I connected a Quantum 4GB grand prix drive to the external 50 pin port,
the machine saw the disk OK with the boot prom monitor but when it tried
to boot UNIX it would not get past SCSI_CAM errors. I should mention that
this drive was originally specified for a Sun system and I have seen on
occasion Sun specific additions to disk controllers that would cause some
generic SCSI adapters to barf. We connected the same drive/cable/term
to a Sun systen and it worked fine.
So we took an older/smaller SCSI-2 Fuji drive off one of our Suns and
tried it on the AlphaStation 600 bus with the same cable/term. It worked!
So my questions are:
Can you (officially) mix 68 pin SCSIs diff and non-diff devices
on the same bus?
Will performance suffer if you mix them?
Will performance suffer for diff devices if one terminated end of the
ribbon cable is missing l8 connections?
Does anyone know if the RZ28M and RRD45 are differential devices? They
have 68 pin connectors but apparently that doesn't necessarily
mean they are differential.
Thanks.
--
---------------------------------------------------------------------------
Ted Asocks tra_at_ucolick.org
Systems Administrator VOICE: (408)459-4020
UCO/Lick Observatory FAX: (408)426-3115
Received on Fri Apr 19 1996 - 01:20:12 NZST