16 Apr
2003
16 Apr
'03
1:30 p.m.
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
SI9900?
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