On 11/1/2022 11:49 AM, Ethan Dicks via cctalk wrote:
I don't think the 11/750 could have handled that
many users on DZ-11s.
I think this is why COMM-IO-P systems were sold. They basically acted
like front end processors for a stack of DZ11's to interface to a Unibus
Problem was those communications processor boards only had enough
microcode to handle either block lines or async lines but not both. When
the fruitcakes at HKJC demanded that they support the betting systems
(polled block oriented devices) and async terminals (for betting odds
and displays and such) for the mighty Sha Tin Totalizer (multiple 11/74
type systems and a boat-ton of 11/04 front ends connected by those weird
IPC connections) all hell broke loose.