DEC M9312 Configs for a 11/40

william degnan billdegnan at
Sun Nov 27 18:28:40 CST 2016

>>> Follow up -
>> I don't think I have issues with my M9312, thanks for your help.   There
>> are a number of candidate issues with my 11/40 which are causing my system
>> to not be able to initiate a bootstrap of the TU58 ROM using the M9312, or
>> bootstrap manually by using the front panel.
>> There is at least partial communication between the TU58 emulator (running
>> on Comm port 3) of my PC, the M7856's jumpers *I think* are correct to
>> serve as the serial card on the PDP 11/40 end.
> So you've verified that the vectors on both your SLUs are correctly set?
I followed the settings found here:

> I have the LTC turned off.
(S59 off / S510 on)

>> There is always more testing I can do, but I suspect my issues are not
>> with
>> the serial card.  Taken holistically, I think there is a DMA UNIBUS issue
>> somewhere.  Just a hunch.
> Can you elaborate on why you suspect this is the case?  Can you describe
> your system in detail?
I have a CPU backplane populated as follows, I have checked the jumpers on
the CPU cards to verify that they're correct to the options installed
1: empty
2: M7253
3: M7232 (1-4) M7237(5)
4: M7231
5: M7233
6: M7235
7: M7234
8: M7236
9: empty with GC
CORE PLANES (2 slots 11-29 has only the first 16K populated.)
9/11: M981 (1-2)
11: M8293 (3-6) (start core plane)
12: M7259 (1-2)
13: G114
14: H217C
15: G235
16-18 empty (removed all core cards)
19/21: M9202 (1-2)
22-29 empty (removed all core cards)
29/31: M9202
31: 7800
32: gc
33: gc
34: 7856
34: M9202
35: gc
36: NPR (jumper was removed at some point)
37: GC
38: 9312 / NPR

>> If anyone knows of or would be willing to make an XXDP TAP image
>> compatible
>> with a 16K PDP 11 I can convert to download via PDPGUI.
> PDP11GUI doesn't use TAP files.  You can use PDP11GUI to load individual
> XXDP diagnostics into the PDP-11 without needing to boot XXDP at all.  Jörg
> has provided a wonderful database of diagnostics here:
> Find the device
> you need to test and grab the diagnostic binaries, listings, and
> documentation and go to town.  (See section 5 of
> -pdp-11-diagnostics-running-them to see how that's done.)

I have done this, some success, but some inconclusive or hard to interpret
(for me).  I  thought I'd have better luck if I installed the entire XXDP
at my skill level anyway.  I am learning a lot but I did not work with this
equipment before.

>   Given I also have
>> issues initiating RL11 bootstrap (with known working equipment),
> What issues are you having?  Does it hang?  Halt?  How are you
> bootstrapping?  I assume you know the RL11 and the RL02 and the pack
> involved are all known-working?
Yes the controller, cable, and disk were tested and working in another
system, recently.  I have more than one working cable and controller.  I
did not personally test the RL02s I have, but one was used a lot by the
previous owner, I have a 2nd that was also used by previous owner before I
took possession of them.

I use both the M9312 DL ROM and manually entering in the bootstrap without
the M9312 installed (replace with terminator card).   With the ROM method
the system repeats an attempt over and over.

system is looping between instructions 173022 -->173156 (error reset the
world), 173160 (retry)..back to 173022

When I first power on the values in the control status register (774400)
are good. 1-6 and 8-13 are cleared, bit 7 is set.
After I attempt to boot (DL at the @ prompt), you can see the light pattern
repeat over and over, looping through 173022 -->173160.
I HALT the system and recheck the control status register. This time
15 - error (composite error (ERR))
10 - EO (operation incomplete (OPI))
7 - stays lit
function code F2 = 1, F1 =1, F0 =0. this code indicates "HFT" (Header Not

To me (and this is just me) the bootstrap is not waking up the RL11
controller, and can go no further.

I am not an expert, just doing the best I can, hope this helps explain.


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