[Info-vax] clock problems with OpenVMS x86 on VirtualBox

[Clair Grant]

On Friday, May 12, 2023 at 1:30:37 PM UTC-4, Simon Clubley wrote:
> On 2023-05-12, Dave Froble <da... at tsoft-inc.com> wrote: 
> > On 5/12/2023 8:14 AM, Simon Clubley wrote: 
> >> On 2023-05-12, Jan-Erik Söderholm <jan-erik.... at telia.com> wrote: 
> >>> 
> >>> Actually, that was how I thought it worked. Since I observed that 
> >>> the clock in my VirtualBox VMS environment lagge a bit behind 
> >>> but each 10-20 sec, it jumpt ahead and skipped a second so that 
> >>> it become in sync with the host Windows environment again. 
> >>> 
> >> 
> >> That's going to make for some "interesting" real-time program behaviour... :-) 
> >> 
> >> Simon. 
> >> 
> > 
> > Do you think any serious real time programmer will run a real time task inside a 
> > VM? I'm not a real time programmer, and I'd still not do that. 
> >
> As well as traditional real-time stuff (which I agree with you about BTW), 
> there's also communications with external devices and the timestamping of 
> received messages, both of which could be affected by such jumps.
> Simon. 
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP 
> Walking destinations on a map are further away than they appear.
Virtual Box 7.0.6, Lenovo ThinkBook, Windows 11

I put SHOW TIME in a 10 minute loop and ran it 7 hours. Every output showed exactly 10 minutes and 0 seconds from the previous. I did the same thing on

ESXi 8.0, DL580

and got the same result. If we have a problem, it is certainly not universal.

Clair