[Simh] How to keep RSTS in sync w/ "wall time"?

[Mark Pizzolato]

Hi Dario,

On Friday, September 9, 2016 at 2:08 PM, Dario Niedermann wrote:
> Il 09/09/2016 alle 18:02, Dario Niedermann ha scritto:
> 
> > it lags behind. Same as when I tried enabling CPU idling.
> 
> I must correct myself: When I enable CPU idling and clock frequency is
> set to 60Hz, RSTS actually keeps correct time (provided I never suspend
> emulation to get to SimH's prompt). It turns out that 'set throttle' was
> canceling the idling (as documented).
> 
> Still, the problem is: With idling and no throttling is my emulated
> PDP11/70's speed realistic - which is what I'm looking for - or is it
> as fast as my hardware can manage?

With idling enabled (or with neither idling nor throttling enabled), the 
simulated PDP11 CPU is running as fast as your host hardware can 
manage, whether this is as faster or slower than an original 
PDP 11/70 will depend on the speed of the host hardware.

With throttling, the logic will attempt to enforce an upper limit on how 
fast it will actually execute instructions.

The fact that when you enable throttling it seems to interfere with the 
delivery rate of simulated clock ticks is a bug.  Please create an issue
at https://github.com/simh/issues to report and track efforts to resolve
this.

Thanks.

- Mark