DEC M9312 Configs for a 11/40

Josh Dersch derschjo at
Sun Nov 27 20:55:52 CST 2016

On 11/27/16 4:28 PM, william degnan wrote:

>>>> 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
> DD11B:
> 31: 7800
> 32: gc
> 33: gc
> 34: 7856
> 34: M9202
> DD11-C:
> 35: gc
> 36: NPR (jumper was removed at some point)
> 37: GC
> 38: 9312 / NPR
Thanks.  Where is the M7762 in this lineup?  You might try shortening 
the bus to eliminate extra variables (the second MM11 backplane, and the 
2nd DD11 backplane can be removed) but you're probably fine.  Based on 
the above, it looks like you've gone over all the grants and have the 
proper continuity cards and/or NPR jumpers in place.  I would also 
suggest cleaning the edge connectors on any that look dirty or oxidized, 
it can and does make a difference (in my experience).

>>> 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.
If you really want to make a bootable XXDP TU58 tape image, the 
instructions given by AK6DN here:

have worked for me in the past.  You can use PUTR to throw more 
diagnostics on the tape if you need.

But you'll need to be able to actually do a TU58 boot, which it sounds 
like you've been having trouble with, so your mileage may vary.

Running the diagnostics stand-alone using PDP11GUI should work fine, and 
I've had good luck with it.  Just be sure to read the diagnostic 
instructions carefully so you know the starting addresses and the proper 
switch settings.  (Sometimes the instructions are in the listing, 
sometimes there's a separate document).

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

According to the user's guide:

If the CSR bits are as you report, the drive got the Read command 
(that's what F0-F2 indicate -- the last selected function, in this case 
"Read Data").  Bit 15 indicates a composite error, and bit 10 indicates 
OPI, as you note.  I don't see anything in there about HFT unless you 
left out some bits.

If indeed bit 12 is set (indicating HFT) then the "Header Not Found" 
indicates that the drive was unable to find the header for the sector on 
the disk, which makes it look like the drive is trying to read but for 
whatever reason isn't able to find the sector.  This could be a damaged 
disk, misaligned heads, or any number of logic failures.

I would start with the RL02/RL11 diagnostics via either XXDP or PDP11GUI 
and go from there.

> I am not an expert, just doing the best I can, hope this helps explain.
Nor am I, but I'm getting better.  The DEC documentation is generally 
excellent, and it helps to have a basic understanding of the instruction 
set.  You might try sitting down with the RL02 user's manual and writing 
some short programs to test out the controller just to see what it's 
doing -- see if you can read in a single sector, etc...

- Josh

> Bill

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