24 Oct
2001
24 Oct
'01
12:31 p.m.
On Wed, 24 Oct 2001, Carlini, Antonio wrote:
Peter Wallace wrote:
Oh, OK its been a looooong time... I just remembered that if it was wrong
nothing worked and there was no indication of what was wrong...
Peter Wallace
Something I remember on RA81s is that you have to
go from
controller --> cable --> bulkhead connector --> cable --> disk
if you go directly from controller to disk, you end up with pins
swapped
and things dont work (but nothing hurt)
I think the rule is you have an *odd* number of
connecting cables - since each cable swaps.
So in a MicroVAX 3600 you can go directly from
KDA50 controller to RA7x internal drive. Or you
can go from KDA50 to bulkhead, bulkhead to
bulkhead on next cab (e.g. storage array) and
from there a third cable goes internally from
bulkhead to final drive.
In the case of a 6000 typically you go from
KDB50 (or KDM70) to bulkhead on 6000 chassis.
Then 6000 chassis to Storage Array chassis.
Then internally there is a cable from the
Storage Array bulkhead to the drive itself.
I don't know how the wiring was done for
those later kits that allowed RA9x and/or
RA7x drives to live in the bottom of
the VAX 6000 chassis.
Antonio