[Simh] TOPS-20 4.1 BUGHLT

[Timothe Litt]

On 10-May-15 14:14, Cory Smelosky wrote:
>
> Sent from my iPhone
>
>> On May 10, 2015, at 13:32, Timothe Litt <litt at ieee.org> wrote:
>>
>>> On 10-May-15 13:07, Cory Smelosky wrote:
>>> Hey,
>>>
>>> Trying to figure out if this is an issue with the install or an
>>> obscure SIMH bug.
>>>
>>> PDP-10 simulator V4.0-0 Beta        git commit id: 3b8c318b
>>> Listening on port 2020
>>>
>>> BOOT>
>>>
>>>
>>> [PS MOUNTED]
>>>
>>> SETSPD: TERMINAL 1-40 SPEED 200
>>>
>>> System restarting, wait...?INVALID CHARACTER IN NUMBER
>>> ENTER CURRENT DATE AND TIME: 10-MAY-2015 13:02
>>>
>>> YOU HAVE ENTERED SUNDAY, 10-MAY-2015 1:02PM,
>>> IS THIS CORRECT (Y,N) Y
>>> WHY RELOAD? OPR
>>> RUN CHECKD? N
>>>
>>> RUNNING DDMP
>>>
>>>
>>> SYSJOB 5(23) STARTED AT 10-MAY-2015 1302
>>> RUN SYS:ORION
>>> RUN SYS:QUASAR
>>> RUN SYS:MOUNTR
>>> RUN SYS:INFO
>>> RUN SYS:MAILER
>>> RUN SYS:MAPPER
>>> RUN SYS:LPTSPL
>>> RUN SYS:LPTSPL
>>> RUN SYS:CDRIVE
>>> RUN SYS:SPRINT
>>> JOB 0 /LOG OPERATOR XX OPERATOR
>>> ENA
>>> ^ESET LOGIN PSEUDO
>>> ^ESET LOGIN CONSOLE
>>> ^ESET OPERATOR
>>> PTYCON
>>> GET SYSTEM:PTYCON.ATO
>>> /
>>> JOB 1 /LOG OPERATOR XX OPERATOR
>>> ENA
>>> RUN SYS:BATCON
>>> /
>>> SJ  1: @LOG OPERATOR OPERATOR
>>> SJ  0: @LOG OPERATOR OPERATOR
>>>
>>> **********
>>> *BUGHLT "ILMNRF" AT 10-May-2015 13:
>>> *JOB: 000000000002, USER: OPERATOR
>>> *ADDITIONAL DATA: 001000746144, 304000000000, 000000537375
>>> **********
>>>
>>> Config:
>>>
>>> set cpu idle
>>> set cpu tops-20
>>> at rp0 tops20-ps-rp06-1.dsk
>>> at rp1 tops20-ps-rp06-2.dsk
>>> at rp2 tsu.dsk
>>> at dz0 2020
>>> set tim y2k
>>> set console wru=6
>>> boot rp0
>>>
>>> I have applied the TSU01 4.1 update.
>>>
>>> Any ideas?  It worked fine until I tried to build kermit.
>> This is the generic illegal memory reference in the monitor for
>> TOPS-20.  Could be a reference to an unmapped page; a stray pointer, or
>> commonly a missing erjmp after a potentially unmapped reference.  There
>> were lots of patches for various cases, but there's probably not a 'last
>> bug'.
> Ahhh. Wonder what caused it? All I recall doing before was building permit.
>
>> The additional data is the pagefail word, flags and pc.
>>
>> The only way to track it down is to get a crash dump and dig in.  (You
>> might get a clue if you look at the PC with MDDT...)
> A bit difficult considering I can't get a successful boot. ;)
>
> SIMH's switch register cheat sheet?
>
>> You might also get a clue if you run spear on the error log.
> Again hindered by an inability to boot. ;)
Well, we know that TOPS-20 boots on SimH when built from scratch.
So the monitor or the disk was probably corrupted.
As usual, you aren't providing enough detail of exactly what you did and
how/when it fails.

While it could be a SimH issue, I'd start by assuming it's a monitor bug
and work backwards.
That's the only way to get close enough to identify an issue, wherever
it is.

So you, or someone with TOPS-20 expertise can:
  boot into EDDT and investigate
  with dbugsw set, stop in MX and determine if one of the programs started
  by MX or sysjob is triggering the bug.  Since the fault is Job 2, that
seems likely.
  set a breakpoint at the bughlt and backtrace.
  boot an older version of the monitor (assuming you kept one)
  generate a suitable patch.

Or since you have backups of all your work, you can just build a new PS,
restore them and see what happens.

I don't have the time to debug this, but there are other folks on the
list who have the necessary skills.


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