topic Re: Set and view Timezones for Puerto Rico and Azores in Operating System - OpenVMS

Set and view Timezones for Puerto Rico and Azores

Cass Witkowski — Sun, 23 Sep 2007 17:00:19 GMT

We recently upgraded to OpenVMS V7.3-2 Alpha. We had a problem with our Puerto Rico site since our timezone rule was deleted since it was in a obsolete timezone rule file. Something about system v.

Anyway I want to me able to 1) specify the correct timezone for Puerto Rico and Azores and 2) be able to examine the rules to verify they are correct.

Thanks

Cass

Re: Set and view Timezones for Puerto Rico and Azores

John Gillings — Sun, 23 Sep 2007 17:23:58 GMT

Cass,
Timezone rules are defined in SYS$TZDIR. See the SOURCES subdirectory for the readable text. You use ZIC (Zone Information Compiler) to compile the source into a binary zone information file. ZIC is a standard Unix utility.

If you know the timezone rules there are several choices:

1) Write the rules yourself
2) Copy the rules from old source code
3) Copy the rules from an equivalent timezone

On the other hand if it's obselete, surely that means both regions now use some other "standard" zone rule and all you need do is switch to that zone? Here's what the V8.3 sources say:

$ search SYS$COMMON:[SYS$ZONEINFO.SYSTEM.SOURCES]*. azores /windo=10

******************************
SYS$COMMON:[SYS$ZONEINFO.SYSTEM.SOURCES]EUROPE.;1

#
# From Paul Eggert (1996-11-12):
# IATA SSIM (1991-09) reports several 1991-09 and 1992-09 transitions
# at 02:00u, not 01:00u. Assume that these are typos.
# IATA SSIM (1991/1992) reports that the Azores were at -1:00.
# IATA SSIM (1993-02) says +0:00; later issues (through 1996-09) say -1:00.
# Guess that the Azores changed to EU rules in 1992 (since that's when Portugal
# harmonized with the EU), and that they stayed +0:00 that winter.
#
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
# DSH writes that despite Decree 1,469 (1915), the change to the clocks was not
# done every year, depending on what Spain did, because of railroad schedules.
***************
0:00 Port WE%sT 1983 Sep 25 1:00s
0:00 W-Eur WE%sT 1992 Sep 27 1:00s
1:00 EU CE%sT 1996 Mar 31 1:00u
0:00 EU WE%sT
Zone Atlantic/Azores -1:42:40 - LMT 1884 # Ponta Delgada
-1:54:32 - HMT 1911 May 24 # Horta Mean Time
-2:00 Port AZO%sT 1966 Apr 3 2:00 # Azores Time
-1:00 Port AZO%sT 1983 Sep 25 1:00s
-1:00 W-Eur AZO%sT 1992 Sep 27 1:00s
0:00 EU WE%sT 1993 Mar 28 1:00u
-1:00 EU AZO%sT

$ search SYS$COMMON:[SYS$ZONEINFO.SYSTEM.SOURCES]*. "Puerto Rico" /window=10

******************************
SYS$COMMON:[SYS$ZONEINFO.SYSTEM.SOURCES]NORTHAMERICA.;1

# Dominican Republic changed its mind and presidential decree on Tuesday,
# November 28, 2000, with a new decree. On Sunday, December 3 at 1:00 AM the
# Dominican Republic will be reverting to 8 hours from the International Date
# Line, and will not be using DST in the foreseeable future. The reason they
# decided to use DST was to be in synch with Puerto Rico, who was also going
# to implement DST. When Puerto Rico didn't implement DST, the president
# decided to revert.

# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule DR 1966 only - Oct 30 0:00 1:00 D
***************
Zone America/Panama -5:18:08 - LMT 1890
-5:19:36 - CMT 1908 Apr 22 # Colon Mean Time
-5:00 - EST

# Puerto Rico
# There are too many San Juans elsewhere, so we'll use `Puerto_Rico'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Puerto_Rico -4:24:25 - LMT 1899 Mar 28 12:00 # San Juan
-4:00 - AST 1942 May 3
-4:00 US A%sT 1946

Since these source files are "standard" across many operating systems, you can use a Google search to look for alternatives, and/or validate what you have.

Re: Set and view Timezones for Puerto Rico and Azores

Cass Witkowski — Sun, 23 Sep 2007 17:43:47 GMT

So it looks like for the Azores the time is either AZOT or AZOST depending on if we are in summer timne.

From your response it wasn't clear what time zone to use for Puerto Rico.

My question also stems from when I am using UTC$TIME_SETUP how do I know I have the correct time. It is not very straight forward.

It looks I can select the Azores time choosing 6 ATLANTIC and then 1 AZORES

But what selection do I use for Puerto Rico?

What is the difference between Pacific and Pacifc-NEW?

Thanks

Re: Set and view Timezones for Puerto Rico and Azores

John Gillings — Sun, 23 Sep 2007 18:14:02 GMT

Cass,

Try 2 (AMERICA) then hit return to go to the second page, then 104 PUERTO_RICO (that's on V8.3, so the numbers might not be identical)

My reading of the comments is that Puerto Rico does not have daylight savings, which means it has a fixed time offset, GMT+4, so you could also use one of the GMT offset rules.

Re: Set and view Timezones for Puerto Rico and Azores

Cass Witkowski — Tue, 25 Sep 2007 13:11:23 GMT

Thanks John!

It would be nice if the UTC$TIME_SETUP procedure would print out a summary of the new setting after you selected a timezone and asked you to confirm your choice.

Cass

Re: Set and view Timezones for Puerto Rico and Azores

Hoff — Tue, 25 Sep 2007 13:26:51 GMT

As for displaying:

@UTC$TIME_SETUP SHOW

See http://64.223.189.234/node/560 for related materials; how to decode the rule format that can be displayed.

Also follow the http://64.223.189.234/taxonomy/term/57 tag around -- Timekeeping -- and you'll have access to a number of detailed and technical articles on time and timekeeping on OpenVMS.

Since we're coming into DST season yet again, any corrections or updates on the above timezone (TZ) and daylight saving time (DST) articles are welcome.

Stephen Hoffman
HoffmanLabs LLC

Re: Set and view Timezones for Puerto Rico and Azores

Cass Witkowski — Wed, 26 Sep 2007 14:13:52 GMT

Hoff,

I like the SHOW option. It would be nice to display this information after you made your selection from the menu and then give you the ability to confirm your choice.

We have been running into issues with OpenVMS changing the time and interactions with NTP. We are seriously considering turing off NTP 30 minutes before the time change and the turing it on an hour later.
(Why can't we all just get along?)

Cass

Re: Set and view Timezones for Puerto Rico and Azores

Hoff — Wed, 26 Sep 2007 15:04:30 GMT

>>> I like the SHOW option. It would be nice to display this information after you made your selection from the menu and then give you the ability to confirm your choice.<<<

Lob an enhancement request at HP. (The fellow that was maintaining this tool has retired a couple of months back -- I don't know if the new maintainer follows postings here our out in c.o.v., nor who that new maintainer might be.)

>>>We have been running into issues with OpenVMS changing the time and interactions with NTP. We are seriously considering turing off NTP 30 minutes before the time change and the turing it on an hour later.<<<

If you're on OpenVMS Alpha or OpenVMS I64 V7.3 or later and with a compatible version of TCP/IP Services (or analogous third-party IP stack), all timezone management is based on the OpenVMS mechanisms. NTP itself doesn't (and has never, AFAIK) had anything to do with the DST switch-over. That's always been handled other code. NTP broadcasts UTC. Now if your NTP server flips its own broadcast time, all bets are off.

>>>(Why can't we all just get along?)<<<

Because timezones are a Canadian invention built on a nebulous foundation and solely meant to ease the lives of nineteenth century railroad barons? :-) (All that is true, BTW.) But seriously, timezones and time and related only look easy -- and managing these while also maintaining compatibility is a non-trivial problem. And once you start out with a non-UTC system time (as is the case on OpenVMS and Windows), the complexity increases.

Most of what I have accumulated on the topic is posted over at the website.

Re: Set and view Timezones for Puerto Rico and Azores

Cass Witkowski — Tue, 16 Oct 2007 18:57:25 GMT

Thanks for your responses.

I have submitted the enhancement request to HP.