[Info-vax] [7.3 VAX] NTP and daylight saving time

[Arne Vajhøj]

On 10/29/2024 9:19 AM, JKB wrote:
> 	My VAX runs OpenVMS 7.3 and I uave configured NTP client some
> 	months ago.
> 
> 	Today, I have seen that clock was not synchronized. SHOW TIME
> 	returns a difference greater than 4 hours between OVMS client and
> 	NetBSD server.
> 
> 	I have restarted NTP.
> 
> $ type TCPIP$NTP_RUN.LOG
> 29 Oct 08:57:13  ntpd version = 4.1.0
> 29 Oct 08:57:14  precision = 10000 usec
> 29 Oct 08:57:16  drift file 'SYS$SPECIFIC:[TCPIP$NTP]TCPIP$NTP.DRIFT' does not e
> xist: no such file or directory
> 29 Oct 08:57:17  will attempt to create drift file
> 29 Oct 09:01:41  time correction of 3607 seconds exceeds sanity limit (1000); se
> $ show time
>    29-OCT-2024 14:15:21
> 
> 	On server side :
> hilbert:[~] > date
> mar. 29 oct. 2024 14:15:34 CET
> 
> 	I have checked timezone with @SYS$MANAGER:UTC$TIME_SETUP.COM and, for
> 	me, configuration correspond to Europe/Paris time.
> 
> 	Server use UTC. For me, client use UTC also and only SHOW TIME does
> 	time conversion from UTC to local time. I suppose I have done a
> 	mistake somewhere, but where ?

"3607 seconds" is likely clock 7 seconds off and time zone 1 hour off.

Has it always been like this or did it happen when Europe switched
to winter time in the weekend?

I suspect that the TZ config may have CET/MET without DST
instead of CET/MET with DST with a wrong clock that gave the correct
result on summer time and and wrong result on winter time. But that
is pure speculation.

Arne