pdp10-ka ITS gets catatonic after a while

[eswenson1]

If I let my KA ITS (running under pdp10-ka) run overnight, or sometimes a little more than overnight, I find that there are hundreds of "EXA ITS revived! messages in my DDT session, and hundreds of "EXA ITS 1652 REVIVED. hh:mm:ss" messages on the system console. Neither session responds to ^Z, or if they do, it is many 10s of seconds later. Then after an initial response, everything hangs for a while, until the next "revived" message. The system is completely unusable at this point, and I have to crash it. I cannot, even if on the console at a DDT prompt, run LOCK successfully. Sometimes I can get it started, but the system hangs and then revives, but never long enough for a shutdown to occur.

Also, typing the simulator escape sequence (^) doesn't respond for quite some time when the simulator is in this state. It may eventually respond with the prompt, and typing the "cont" command goes back to the wedged state. Sometimes, I can force a return to DSKDMP, but most time, I can never get things back working. I have to simply quit the simulator (if I can get to the prompt) or kill the process (if I can't).

[eswenson1]

Sometimes I can get LOCK to schedule the system to go down, but it doesn't:

$$u
 LOGOUT ___014 0 10:11:52

EXA ITS 1652 SYSTEM JOB USING THIS CONSOLE. 10:11:52

EXA ITS 1652 GOING DOWN IN 00:04:57.   10:11:52

EXA ITS 1652 GOING DOWN IN 00:04:57.   10:16:50

EXA ITS 1652 GOING DOWN IN 00:04:57.   10:23:09

EXA ITS 1652 GOING DOWN IN 00:04:56.   10:29:28

EXA ITS 1652 GOING DOWN IN 00:04:56.   10:36:06

EXA ITS 1652 GOING DOWN IN 00:04:55.   10:42:25

EXA ITS 1652 GOING DOWN IN 00:04:55.   10:49:59

EXA ITS 1652 GOING DOWN IN 00:04:54.   10:56:36

EXA ITS 1652 GOING DOWN IN 00:04:54.   11:02:56

EXA ITS 1652 GOING DOWN IN 00:04:53.   11:09:52

EXA ITS 1652 GOING DOWN IN 00:04:53.   11:15:53

EXA ITS 1652 GOING DOWN IN 00:04:52.   11:22:31

EXA ITS 1652 GOING DOWN IN 00:04:52.   11:28:13

EXA ITS 1652 GOING DOWN IN 00:04:51.   11:34:50

EXA ITS 1652 GOING DOWN IN 00:04:51.   11:41:28

EXA ITS 1652 GOING DOWN IN 00:04:50.   11:47:48

[larsbrinkhoff]

Is this on a VPS or some kind of virtual machine? Twice I have problems running on a VPS. First it broke klh10 (another failure mode though). Now since a few months back, I can no longer run pdp10-ka despite not having changed anything on my end. I also get those "ITS REVIVED" messages after, say, roughly 10 or 24 hours or so.

I have no problem running on my own physical machines, PC type or Raspberry Pi.

[eswenson1]

This is on my M1 Mac. No VPS.

[eswenson1]

It MAY have something to do with the Mac going to sleep and then waking up from sleep.