Fw: 4D 220 VGX: free for Shipping or Orlando,FL pickup

From: Corda Albert J DLVA <CordaAJ_at_NSWC.NAVY.MIL>
Date: Mon Oct 28 16:04:00 2002

The older SGI 4D twin towers (professional series) used a SCSI bus
that was routed through a connector arrangement up through the
smaller drive tower. Unfortunately, I seem to remember that
because of the stub length off of these connectors, it violated
the SCSI specs pretty badly. My guess is that because the early
CPU cards that were fitted in these systems (IP4 and IP4.5) only
supported async. scsi, they were more forgiving than a sync. system
would be. BTW, I believe that one of the reasons for using ESDI vs.
SCSI in these critters was that, at the time, the ESDI drive/controller
combo was quite a bit faster than async. SCSI. They intended the
SCSI interface for peripheral access only...

That said, I did manage to get a SCSI drive working in one, but
since I had the ESDI controller and drives, it didn't seem worth
it at the time to pursue it further...

As far as the twin tower power series, my memory fails me... I don't
remember when they began supporting sync. SCSI, but my guess is
that it began with the power-series CPU boards.

-al-
-acorda_at_1bigred.com



> -----Original Message-----
> From: Tothwolf [mailto:tothwolf_at_concentric.net]
> Sent: Monday, October 28, 2002 2:16 PM
> To: cctalk_at_classiccmp.org
> Subject: Re: Fw: 4D 220 VGX: free for Shipping or Orlando,FL pickup
>
>
> On Mon, 28 Oct 2002, Will Jennings wrote:
>
> > Eh? How are they SCSI? I had one of these once, the drive
> in it was most
> > definetly a Hitachi ESDI disk... They're such cool looking machines,
> > too...
>
> If the system is a dual tower configuration, it almost always
> uses ESDI
> drives, but the single tower deskside 'cubes' always have a
> SCSI bus in
> them. AFAIK, the dual tower was retired around the time of
> the 2x0, so I
> guess it could indeed use ESDI drives. I have yet to have
> seen a 2x0 in a
> dual tower, but I suppose they might exist. A photo of the
> system itself
> would pretty much clear it up.
>
> The cpu boards in these are actually interchangeable for the
> most part,
> and the deskside chassis can accept up to two such boards
> with up to two
> cpus each for a total of 4 processors. The predator rack
> chassis support
> up to 4 cpu boards for a total of 8 cpus.
>
> -Toth
>
Received on Mon Oct 28 2002 - 16:04:00 GMT