I can not speak for VMS, but I can speak for NT and Tru64.
The official (standard) DEC SCSI (and Sun Solaris) controller was based on the QLogic
device in ISP*40/50/60/80 boards. I do not remember why we picked them, there must have
been features that Adaptec did not support that Qlogic did. My memory is they were
"triple" board that supported Network, SCSI and something else -- ???floppy
maybe??.
At the that time ( mid late 1990s ) NT did not work/support/was qualified with the
Qlogic (NT only supported the NCR, LSI/Buslogic and Adaptec chips). Thus DEC had to
ship the 2940 based in the Alpha/NT systems. This forced the boot ROMs from then on to
have the code to deal with them. IIRC from Turbo lasers on that code to support Adaptec
SCSI chips was "in there."
At the time, I do not believe the Tru64 SPD officially support them (I do not remember the
details - there was some issues with fail-over on TruClusters), but the OS could recognize
them, and even boot from them and a lot of smaller machines, particularly repurposed
Alpha/NT systems ran that way (the Tru64 based Alpha on my own desk in MRO & ZK0 had
one in it -- as did most if not all of them in our Lab).
When we trying to build the $1K Alpha (i.e. we replaced the Compaq based AMD K8 with and
EV6 - long story), we used the Adaptec board so Tru64 could "just work" and I
seem to remember there was an issue with Qlogic boards which was never solved. (Too many
beers ago, but I know VMS would not boot but I've forgotten why. I think I remember
that it was because VMS did not have the native support for the Adaptec chips).
Funny - years later, I do not think I have Qlogic boards in my "museum" - but I
know I have 4 or 5 Adaptecs in box somewhere.
On Thu, Feb 14, 2013 at 11:16 PM, Dave McGuire <mcguire at neurotica.com> wrote:
On 02/14/2013 11:15 PM, Cory Smelosky wrote:
Mine are pretty much like those, except the internal
connector is
parallel, they work with VMS, and they're not parallel SCSI inside.
If they're not parallel SCSI inside, then what are they?
The ISP1080 (I think you mentioned your board is ISP1080-based) is a
pretty common PCI to SCSI host adapter chip. Nearly all of the required
circuitry is on that chip.
What Gregg was looking for was, I think, something from the Adaptec
AHA2940 family. Different chip, same basic idea, just as common, but
incompatible at the register level.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA