On Aug 20, 2021, at 4:31 PM, John Forecast via cctalk
<cctalk at classiccmp.org> 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