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UCX - NTP and UTC time difference

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Raymond P. Manyik
Occasional Advisor

UCX - NTP and UTC time difference

I was able to set up NTP on UCX on a VAX here this summer without any issues. When I tried setting up others I noticed that it still has a 7 hour time difference from UTC. The logical is correct for the UCX time zone and the logical ucx$tdf is -8 (I am on the west coast of US). The log for the ucx$ntpd indicates the following line:
* Timezone Differential Factor is -25200

Can anyone tell me where the NTP client gets its time differential. The template file to set up the configuration is misleading in that the example for setting up UCX$NTP_TZ doesn't make sense. -40000 is not the number of seconds between UT and Boston in the summer. The logical name is not defined by the system.

Thanks for any help.

Ray
14 REPLIES
Mike Reznak
Trusted Contributor

Re: UCX - NTP and UTC time difference

Hi,
look for the SYS$TIMEZONE_DIFFERENTIAL logical. If it's there you should see -25200 which is -7hours
It can be changed via SYS$MANAGER:UTC$TIMEZONE_SETUP.COM.

Mike
...and I think to myself, what a wonderful world ;o)
Ian Miller.
Honored Contributor

Re: UCX - NTP and UTC time difference

You may have to set the time zone stuff in UCX as well as on VMS for older versions.
UCX SET CONFIG TIME "..."
then do
UCX GENERATE TIME
to update the logicals and then restart your NTP server to pick up the result.
____________________
Purely Personal Opinion
Michael Yu_3
Valued Contributor

Re: UCX - NTP and UTC time difference

Hi Ray,

You must be running an old version of TCP/IP services for OpenVMS. The logical UCX$NTP_TZ is in hhmmss format. So -40000 means 4 hours behind UTC and 100000 means 10 hours ahead of UTC.

The logical sys$timezone_differential is in seconds. So -14400 is 4 hours behind UTC and 39600 is 11 hours ahead of UTC.

If a system has both of these logicals defined, UCX$NTP_TZ will be ignored
and SYS$TIMEZONE_DIFFERENTIAL will be used to define the time zone offset.

The timezone differential factor you showed is 7 hours behind UTC. If the real TDF is -8 hours, you can use UTC$TIME_SETUP to set up your timezone differential and your system time correctly.

Thanks and regards.

Michael

Raymond P. Manyik
Occasional Advisor

Re: UCX - NTP and UTC time difference

Thanks to you guyus for your reply.

I think that the SYS$TIMEZONE_DIFFERENTIAL logical will probably be the key. I ran the UTC$TIMEZONE_SETUP file and checked the logical and it did not change. I rebooted and it still did not change. I then tryied editing the UTC$TIMEZONE_SETUP.COM file and it appears that the data comes from binary files, one per unique time zone. I searched sys$manager:*.com for SYS$TIMEZONE_DIFFERENTIAL, but it is not defined there. I do get the correct answers on the screen for time zone and differences in hours. Perhaps there is something I missed. Or is there someplace where I could write a command file to look at the time and re-define SYS$TIMEZONE_DIFFERENTIAL after it gets defined by whatever generates the logical and before UCX$NTPD is started. How about in UCX$NTPD_STARTUP.COM? That, of course, does not handle running durring the time change (to/from DLS from/to standard)

Any help/hints would be appreciated.

Thanks
Ray
Michael Yu_3
Valued Contributor

Re: UCX - NTP and UTC time difference

Hi Ray,

Which version of OpenVMS are you running? Depending on the version and whether you are using DTSS, the source of the timezone differential may be different. It might be coming from sys$update$timezone_rules.dat or SYS$SYSROOT:[SYS$ZONEINFO.SYSTEM.SOURCES]NORTHAMERICA. (source for the timezones in North America, any change to it will need recompiling using ZIC).

Please post the output of

SHOW LOGICAL *TIME*

Thanks and regards.

Michael
Raymond P. Manyik
Occasional Advisor

Re: UCX - NTP and UTC time difference

Here is the output from show logical *time*


"CHS_TIME" = "MBA31:"
"DHS_TIME" = "MBA32:"
"SYS$LOCALTIME" = "SYS$SYSROOT:[SYS$ZONEINFO.SYSTEM.US]PACIFIC."
"SYS$TIMEZONE_DIFFERENTIAL" = "-28800"
"TIMEDATE_IS_DST" = "0"

Note that I made the change to the UCX$NTP_Startup.com to set the logical SYS$TIMEZONE_DIFFERENTIAL to the correct value. Without my changes it displays -25200.

Here is the version information on the system.

UCX> show version /all

Digital TCP/IP Services for OpenVMS VAX Version V4.1
on a VAXstation 4000-90 running OpenVMS V7.1

Thanks
Ray
Bradford Hamilton
Regular Advisor
Solution

Re: UCX - NTP and UTC time difference

Hi Ray,

@sys$examples:daylight_savings.com

Theis will queue a batch job to be run at your choosing to change the TDF (and local time, if needed). The prompts are fairly straightforward.
Michael Yu_3
Valued Contributor

Re: UCX - NTP and UTC time difference

Hi Ray,

You are running V7.1 of OpenVMS and you have set your timezone to US/PACIFIC.

From the output of show logical *time*, you are not using DTSS.

You were running in daylight saving time before the last Sunday of October. Since you are using V7.1 and not using DTSS, there is no automatic TDF change made when daylight saving ended on Oct 30. Hence you have the problem of still having the TDF as -7.

So what you need to do is to use DAYLIGHT_SAVINGS.COM to perform the manual daylight saving change.

If you were using DTSS, then it can help you perform the automatic TDF change.

If you were using V7.3 or later, the sysgen parameter AUTO_DLIGHT_SAV also helps you with automatic TDF change.

Thanks and regards.

Michael
Bradford Hamilton
Regular Advisor

Re: UCX - NTP and UTC time difference

"If you were using V7.3 or later, the sysgen parameter AUTO_DLIGHT_SAV also helps you with automatic TDF change."

The OP is using VAX - AUTO_DLIGHT_SAV is Alpha-only; never made it to VAX.
Michael Yu_3
Valued Contributor

Re: UCX - NTP and UTC time difference

Hi Bradford,

Yes, AUTO_DLIGHT_SAV is Alpha only. Thanks for pointing that out.

Thanks and regards.

Michael
Alex Daniels
Frequent Advisor

Re: UCX - NTP and UTC time difference

AUTO_DLIGHT_SAV is _not_ Alpha only.

It's present on all VMS 64bit platforms, and worked perfectly on my Itanium boxes last week.
Raymond P. Manyik
Occasional Advisor

Re: UCX - NTP and UTC time difference

Thank you all for your responses. I am on a trip and will not be back at the office for the next couple of weeks. I will try the example command file and see if there takes care of it all.

Michael, is DTSS a part of UCX that I could turn on or is it another product?

If I am going to set up a batch file to â resetâ the time difference and local times, do I need to restart the NTPD process or does it check the time difference logical on a periodic basis? If I need to kill is should I just use the VMS commands to blow it away or is there some suggested UCX commands to just stop and restart that one process?

Thank you again for the help. The message from Mike Reznak was a big key to get me to a place where I only have a problem twice a year. If I can get it set up to run on its own, that would completely close it out for me. Since I wonâ t be back in the office for a couple of weeks this thread will be in limbo.

Thanks
Ray
Michael Yu_3
Valued Contributor

Re: UCX - NTP and UTC time difference

Hi Ray,

DTSS is part of DECnet/OSI.

You can stop NTP with UCX$NTPD_SHUTDOWN.COM and start NTP with UCX$NTPD_STARTUP.COM.

NTP should be sending and receiving UTC time. The system time displayed will use the timezone differentials.

Thanks and regards.

Michael
Raymond P. Manyik
Occasional Advisor

Re: UCX - NTP and UTC time difference

I believe that I now have enough information to be able to set up the system to operate with NTP and to make the transitions to and from DST.

Thanks for all the help

Ray