> On Aug 20, 2021, at 4:31 PM, John Forecast via cctalk <[email protected]>
> wrote:
>
> See:
>
> <https://www.miim.com/faq/hardware/multipro.shtml#qbus
> <https://www.miim.com/faq/hardware/multipro.shtml#qbus>>
>
> for more info on multi-processor PDP-11s including KDJ11-B’s.
>
> John.
Nice.
Interestingly enough, I remember another machine that was also called 11/74; it
existed in the RSTS/E lab in Merrimack (NH). That one wasn't an MP machine;
instead, it was an 11/70 with additional microcode to add the CIS (strings and
decimal arithmetic) instruction set. COBOL-11 could use this, and indeed CIS
was a supported product in some later machines. But the 11/74 CIS machine
never saw the light of day.
I don't know why not. Perhaps it was not cost-effective given that it was a
physically large machine, no longer a state of the art architecture for the
time (around 1980). One comment I heard is that it was forced to be canceled
because it could run COBOL faster than a VAX-11/780. No idea if that was true
(either the speed claim or the cancelation claim). It has a faint ring of
plausibility to it; when the 780 came out, DEC made some noises that PDP-11
would disappear within just a handful of years. It didn't take them all that
long to realize the absurdity of that notion.
paul
