VMS - change from EDT to EST - have question about daylight_savings.com

[Layne Burleson_1]

Volker,
I did a difference on the file you sent me and the file I have on 7.3-1. They are the same. I thought that to be rather weird.
Layne

[Martin P.J. Zinser]

Hello Layne,

now you made me do it ;-) I've actually looked at the procedure.

The invocation of utc$time_setup.com quoted by
Volker can be used verbatim. RULE is not some
symbol set earlier in the procedure but a keyword expected by utc$time_setup.com.

So go ahead, run it and check if your logicals get defined correclty.

Greetings, Martin

[Layne Burleson_1]

Martin,
I just ran and this is what I get:
$ sho lo *timez*

(LNM$PROCESS_TABLE)

(LNM$JOB_8132F740)

(LNM$GROUP_000001)

(LNM$GROUP_000250)

(LNM$SYSTEM_TABLE)

"SYS$TIMEZONE_DAYLIGHT_SAVING" = "0"
"SYS$TIMEZONE_DIFFERENTIAL" = "-18000"
"SYS$TIMEZONE_NAME" = "EST"
"SYS$TIMEZONE_RULE" = "EST5EDT4,M4.1.0/02,M10.5.0/02"

(LNM$SYSCLUSTER_TABLE)

(DECW$LOGICAL_NAMES)
$ sho time
9-NOV-2004 15:15:54
$ @sys$examples:daylight_savings.com

Are you changing to DAYLIGHT or to STANDARD time? (DAYLIGHT/STANDARD): DAYLIGHT

Will the sysman be on this NODE only or CLUSTER wide? (NODE/CLUSTER): NODE

If you choose to SAVE the procedures, you can modify
the SYSMAN environment, or make other changess before executing.

Do you wish to EXECUTE the change now, QUEUE it for future execution,
or SAVE the created procedures without executing?
(EXECUTE/QUEUE/SAVE): EXECUTE




Created file $1$DKA100:[VMS$COMMON.SYSMGR]DST$CHANGE.COM

Is it O.K. to execute the time sysman now? (Yes/No): YES

Configuring the Time Differential Factor (TDF)


$ @SYS$MANAGER:UTC$TIME_SETUP "" RULE

$ SHO LO *TIMEZ*

(LNM$PROCESS_TABLE)

(LNM$JOB_8132F740)

(LNM$GROUP_000001)

(LNM$GROUP_000250)

(LNM$SYSTEM_TABLE)

"SYS$TIMEZONE_DAYLIGHT_SAVING" = "0"
"SYS$TIMEZONE_DIFFERENTIAL" = "-14400"
"SYS$TIMEZONE_NAME" = "EST"
"SYS$TIMEZONE_RULE" = "EST5EDT4,M4.1.0/02,M10.5.0/02"

(LNM$SYSCLUSTER_TABLE)

(DECW$LOGICAL_NAMES)
$ SHO TIME
9-NOV-2004 16:17:04
$

Notice that the daylight savings and timezone name did not change to 1 and EDT.


I really appreciate your input.
Layne

[Volker Halle]

Layne,

it looks like you need to be in the appropriate time zone interval (EDT or EST), to allow the procedure to change those 2 logicals: SYS$TIMEZONE_DAYLIGHT_SAVINGS and SYS$TIMEZONE_NAME.

You tried to change to EDT (DAYLIGHT) on 9-NOV-2004, which is clearly outside the valid DST interval as defined in the rule:

SYS$TIMEZONE_RULE" = "EST5EDT4,M4.1.0/02,M10.5.0/02
(DST = Daylight Savings Time EDT goes from 1st sunday in April until last Sunday in October).

Try to set your system time to 1-OCT-2004 and then change to EDT (DAYLIGHT). Then set the time to 1-NOV-2004 and change to EST (STANDARD).

I tried this on my E8.2 system with MET and MET DST and those 2 logicals changed as expected.

You might want to do this on a test system to not confuse anything related to timestamps !

Volker.

[Volker Halle]

Layne,

your DAYLIGHT_SAVINGS.COM (dated 31-MAR-2004) has come from VMS731_TDF-V0500, so this explains why it could be the same version as included in E8.2

Volker.

[Layne Burleson_1]

Volker,

I think you have solved my problem.... Let me make sure I understand... The SYS$TIMEZONE_RULE determines when the logicals get set and since I am trying to run it outside of that window, it is not changing. Is it possible to modify that rule to run a test?

You have been most helpful and I really appreciate it.

Layne

[Volker Halle]

Layne,

yes, these are my conclusions from your (and my) experience when playing with DAYLIGHT_SAVINGS.COM - and it makes sense to me, that nobody has bothered to test switching to daylight savings time during the winter season ;-)

Changing the rule for a test (I assume you don't want to change the time too much):

I must admit, that I still have not fully understood, where the real source of the timezone rule definition is located.

If DECnet-OSI is installed and you're using DTSS, it seems to come from DTSS$TIMEZONE_RULES.DAT.

I only know that invoking @SYS$MANAGER:UTC$TIME_SETUP is the only supported and reliable way to change these settings in the running system.

Just re-defining the translation of SYS$TIMEZONE_RULE may not work, but you could try. I ran my tests on a test system after a minimum boot.

Volker.

[Layne Burleson_1]

Volker,
I'll try proceeding in that direction. I still run Decnet phase IV. I've got a contact in HP support that used to be my TAM. She is working on a timezone problem and I've asked her to explain the timezone rule. I'll pass any info I receive on to you so that we can clear up this mystery.

Thanks again for helping.
Layne

[Martin Vorlaender]

Volker,

>>>
I must admit, that I still have not fully understood, where the real source of the timezone rule definition is located.
<<<

The FAQ has a complete chapter about VMS system time, time keeping, daylight savings, etc.

See http://h71000.www7.hp.com/wizard/faq/vmsfaq_004.html#time4 for explanations about timezones.

cu,
Martin

[Robert_Boyd]

I've worked with situations where we had systems running NTP, DTSS, both and neither all in the same environment. Since there were so many systems, I wrote a command procedure that works correctly up through VMS V7.3-2 in all the cases I've dealt with so far.

This assumes that you've already executed the proper timezone setup procedure as relates the the system you're on.

Here is the command procedure as an attachment.
I'd be curious to see any feedback about how it is affected by changes in V8.x

Robert Boyd