new gifts

From: Jeffrey Sharp <>
Date: Wed Apr 16 20:30:00 2003

On Wednesday, April 16, 2003, Ethan Dicks wrote:
> My first 11/750 had an SI9900 on it from the day it was used by the
> original owner. My 11/70s also have SI9900s - they are, in their simplest
> form, a 5.25"-tall rack-mounted box with cards that talk to hosts (over
> MASSBUS for the 11/750 and 11/70; over Qbus or Unibus for "lesser"
> machines), and cards that talk to drives (SMD, as far as I've seen). You
> can pack several of each kind on their respective sides of the enclosure.
> The 11/750 controlled two drives and had a total of three cards (one host,
> two drive)
> [...]
> The 11/70s also came with SI-badged tape drives, in 60" Corporate-Cab-
> style cabinets.

The previous owner of my SI9900s said he had problems getting it to work
between some CDC 9762s and a Unibus PDP-11. He said that it liked to
perform a spiral write for him at inopportune moments. I didn't get much
more information than that. He was certain that the SI box was at fault.
Has anyone, by chance, heard of anything like this before regarding the

And when it interfaces to Qbus/Unibus, what does it look like to the rest of
the system? MSCP? Or maybe it was configurable?

Jeffrey Sharp
Received on Wed Apr 16 2003 - 20:30:00 BST

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