[Simh] Simulator lockup when booting RSX-11/M+ V4.6 BL87 baseline system disk with insufficient memory

[Mark Pizzolato - Info Comm]

On Wednesday, January 22, 2014 at 8:17 AM, Christian Gauger-Cosgrove wrote:
> Hello:
> 
> I've noticed an odd issue. When booting the aforementioned baseline RSX-
> 11/M+ disk, with 256K of memory, RSX-11 doesn't have enough RAM to work
> when it tries to run the startup script. This happens as the system doesn't
> have enough memory to allocate a checkpoint space; so
> RSX-11 gets stuck in an infinite loop repeating:
> <TIME>  *** GEN    Checkpoint space allocation failure
> Where <TIME> is the current time in HH:MM:SS format. The CPU is working,
> as you can see the time field counting properly. However, the simulator
> completely locks up otherwise; you can't Ctrl+E to the sim> prompt, you can't
> Ctrl+C or Ctrl+Z the program within RSX-11 itself.
> Trying to exit the SIMH simulator doesn't work. The only way to kill it is via
> the task manager (on Windows).
> 
> I'm using the 14 day old Windows binary. Currently this is happening on a
> Windows 7 Professional SP1 workstation at my university. I'll have to check
> on my W7 Pro SP1 desktop at home, just to see if it is a problem with this
> specific machine, or with the executable itself.
> 
> 
> Regards,
> Christian

Hi Christian,

Thanks for this report.  

This does sound odd.  

I can't speak to what to expect when you configure a simulator with insufficient resources for the operating system to run, but your observation that Ctrl-E doesn't provide a way back to the "sim>" prompt suggests something strange in the simulator itself.

Please create an issue at https://github.com/simh/simh/issues to report and track this problem.

I doubt it has anything to do with the particular windows system you are running on, so you don't have to run back home to test.  The configuration file you're running with would be useful.

Thanks.

- Mark