12 Feb
2015
12 Feb
'15
2:24 a.m.
On 2015-02-11 20:55, Eric Smith wrote:
On Sat, Feb 7, 2015 at 7:25 AM, Paul Birkel
<pbirkel at gmail.com> wrote:
I don't think that 11/72 is a valid designation. All documentation I've
read only calls it an 11/74, no matter how many CPUs you have.
You can find documentation on the MKA11 in the 11/74 documentation.
(See
http://bitsavers.trailing-edge.com/pdf/dec/pdp11/1174/EK-70MP-TM_PRE_1170mp…)
And in there, you can find that:
M8162 is a "Multiport Multiplexor Module"
and
M8163 is a "Single Port Jumper Card".
So yes, both of these cards are for the MKA11.
I would guess that you use the M8163 if you have an MKA11 but just a
single CPU.
I don't understand the role of the M8162
"Port MUX A module" and M8163
"Port MUX B module" that the field-guide claims to be part of the MK11.
They aren't part of the MK11 as far as any documentation that I've read
regarding it. [...]
Do these modules really belong to the MKA11, rather than the MK11?
The MKA11 was the multiported version of the MK11, intended for
multiprocessor (11/72 and 11/74) systems. it makes sense that it would
have some "port mux" modules, though I've never seen any documentation
on it. Reportedly some 11/70 systems were sold to AT&T
with the KB11-CM CPU
and MKA11, apparently just as a way to use up the hardware that was
built for the cancelled 11/74.
I've heard similar. And also that CPU cards for the 11/74 were installed
in 11/70 systems. The differences don't matter for normal operation, and
it will work like a normal 11/70. You can detect if differences if you
try, but the system will work like any other 11/70.
Only a few CPU modules differ between an 11/70 and 11/74 anyway.
Johnny