On Tue, Nov 18, 2014 at 2:22 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
wrote:
From: John
Wallace
Perhaps not so obviously,11/23 boards were
available in variants with
or without floating point, and (iirc) with or without memory
management
unit (MMU) (correction welcome).
No, you're right on target. (Although one couldn't have FP without the MMU;
the FP registers were actually in the MMU chip, see MicroComputers+Memories
'82 pp. 350-351.
is it vaguely conceivable that the diagnostic in
question needs a
piece
of hardware that isn't on the board in
question
Hmm. Possible, but from what I know, unlikely. That test claims to test:
Part 1 - the CPU checks out the basic PDP11 instructions in every
addressing
mode with various data patterns.
Part 2 - tests all trap instructions, trap overflow conditions R6,
interrupts, the reset and wait instruction.
Part 3 - tests the EXTENDED INSTRUCTION SET, the ASH, ASHC, MUL and DIV
instruction
all of which are, AFAIK, part of the basic chip. (Unlike the 11/03 and
11/40, where MUL et al are part of the optional EIS.)
Although I see 'interrupts' listed there - I wonder what they are using
to generate the interrupt? The console serial line? Must be, I can't think
of any other device in the config he was testing.
Ben, you didn't have a discontinuity in the grant jumpering, did you?
What kind of backplane do you have, and in what order/slots were the
boards plugged in?
or is seriously broken on the board in question?
That is the other possibiliy.
Ben, do you get the same error with both CPU cards? Do you have spare
memory/serial line cards you can swap in?
Noel
I don't believe I have any discontinuity, but how would I tell? I think
with my backplane (H9273) I'm supposed to put everything down the left
side, with the BVD11 at the bottom.
Currently I have starting from the top left and going down the left side:
M8186, M8044, M8043, then the BVD at the very bottom.
The only other CPU card I have is the one with that mod and no jumpers. I
did swap the CPU And MMU chips, and they both seem to do the same thing.
I'll add jumpers to the other CPU board and try it out as well!
I have another memory board, but I know it's bad, so I can't try that!
Thanks!
--
Ben Sinclair
ben at