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

[Simon Clubley]

On 2023-05-15, Jan-Erik Söderholm <jan-erik.soderholm at telia.com> wrote:
>> 
>> On 5/12/23 3:25 PM, Clair Grant wrote:
>>> 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'm not sure I fully understand how that test was done.
>
> If you ask VMS to wait for 10 min and then ask VMS for the time
> passed, I would expect VMS to say that "10 min has passed", no
> matter how long those 10 min was in reallity.
>

I agree. I don't think it's a real test unless both VMS and the host OS
are both doing other things while also running this timing loop and there
is a way to compare the reported VMS time with the underlying host OS time.

> Of course VMS in it self belives that 10 min has passed,
> it doesn't know better, so to speak.
>
> Or, fully possible of course, I'm just missing something here... :-)
>

I don't think you are. I think for the test to be valid, it needs to be
done on a loaded system and a way of comparing the VMS reported time to
the actual host time needs to be devised.

Given the reported problems, I also think the test needs to have an
test interval that's way under 10 minutes.

It needs some kind of script, running on the host OS, that is connected to
VMS and runs a $ SHOW TIME every couple of minutes for several hours.

It needs to write both the output from $ SHOW TIME and the current host
time to a log file, along with the delta difference value between the two.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.