[Info-vax] Openvms AXP clock problem

[Stephen Hoffman]

On 2016-10-14 21:22:16 +0000, sandrokan at sandrokan.it said:

> Dear All,
> I have a strange problem with my DEC 2000 axp running openvms 6.2

That is the Jensen or related and that's a problematic system to start 
with, and a very old OpenVMS version.   Get as far forward as that 
particular Alpha supports — IIRC, Jensen was de-supported somewhere in 
the V7 range.   That's one of the few Alpha systems that was 
de-supported by OpenVMS, too.    That box is massively sensitive to the 
system hardware configuration, and all sorts of odd behavior can arise.

> The system boots fine and works fine. The problem comes when I shutdown 
> the system. If I keep it off for 30 minutes and I boot it again the 
> system time is 30 min delayed. In other words instead of following the 
> hardware clock the VMS  is continuing with the time of the last 
> shutdown.
> I imagine that there is a parameter in sysgen or similar that should 
> tell the VMS to follow the hardware clock but I could not find it.

No such parameter exists, nor any such mechanism.

> I also looked online but the only problems reported where about the 
> continous request of date and time at boot (this doesn't apply to my 
> issue)

Make sure that your timezone is set appropriately or — given the 
problems with timekeeping that far back — set your system time to UTC 
and leave it there.   There were some patches to fix bugs in that 
daylight saving time and related pieces, too.   Half-hour offsets 
aren't common, but they do exist.   These offsets do not vary by system 
shutdown time, however.

If NTP is configured and enabled, then confirm you're not using NTP 
servers with problematic time values, and confirm that your time 
synchronization is (not) too far outside of what NTP allows.   That 
usually doesn't manifest by a half-hour slip secondary to a half-hour 
power-down, however.

Assuming you're not powering off OpenVMS hard — performing a hard 
power-off doesn't update the saved system time, and which can lead to 
skewed times — and assuming that you're not using an NTP time server, 
and assuming this isn't secondary to the daylight saving time and 
timezone settings, then replace your watch battery or Dallas chip or 
whatever that Jensen box used.

I'd likely go for a pre-emptive replacement of the battery or the 
Dallas or whatever that box had, anyway.   The boxes with lithium 
batteries only lasted five to ten years. then things got weird.

Related:
http://labs.hoffmanlabs.com/node/441
http://labs.hoffmanlabs.com/node/1078
http://labs.hoffmanlabs.com/node/1895


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