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SCO Timezone changes

© January 2007 Anthony Lawrence


Given SCO's financial troubles, I have to wonder whether they'll issue a patch to fix the upcoming changes to DST in 2007. Fortunately, it's easy to fix this yourself by modifying /etc/TIMEZONE.

As I'm in Massachusetts, I'd change TZ=EST5EDT to TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00 and reboot. That's simple enough, but what does it mean?

If you look at the man page for this file (man F timezone), it all becomes clear. The new DST begins at 2:00 AM on the second Sunday of March and ends at 2:00 AM on the first Sunday of November, That's expressed in TIMEZONE as "Mmonth.week.day/time,month.week.day/time". March is the third month, Sunday is day 0, and we want the second week, so M3.2.0/2:00:00 is what we want for start and M11.1.0 is the end. You could leave off the "/2:00:00" because 2:00 AM is the default.

It's that simple.

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Mon Jan 29 15:15:14 2007: 2839   bruceg2004

What about linux, is that similar? I have some old linux servers that would be nice if I did not have to upgrade them, and do a fix like this.

Mon Jan 29 15:24:08 2007: 2840   TonyLawrence

Linux does it differently - what to do depends on your distro..

Mon Jan 29 15:33:55 2007: 2842   TonyLawrence

(on many, "zic" will compile the tz info)



looks like a good link..

Mon Jan 29 16:03:36 2007: 2843   bruceg2004

Funny, I was just finishing up reading that same link!

Also, I found this site, for new tzdata to be used with 'zic'


Looks like I am not the only one running older unsupported Redhat distros inhouse, firewalled off from the world :-)

- Bruce

Tue Jan 30 18:00:27 2007: 2845   TonyLawrence

Bill Brier pointed this new ta out:


Wed Feb 7 17:04:56 2007: 2854   Donald

Did someone ever tested it?

Thu Feb 8 14:35:42 2007: 2856   BigDumbDinosaur

Did someone ever test what?

Thu Feb 15 22:10:54 2007: 2861   TonyB

Will this work on SCO 5.0.0?

Fri Feb 16 03:26:49 2007: 2862   TonyLawrence

Editing /etc/TIMEZONE will work, yes. But not the MP5 obviously.

Fri Mar 2 21:26:33 2007: 2888   anonymous

Chris Herbsen tells us:

Just one more note on dst, sco 5.0.7.
I discovered that my problems with testing the new dst come from an intrinsic problem with sco ( and other unixs?); you CANNOT change date/time during the several months of dst, or the clock becomes very erratic, and races ahead, only settling down when the system is rebooted, remaining at the time
it raced ahead to. I discovered this when using asktime (or at boot time) to change the date to 1 minute before the november date to test the fall back from dst. In fact any time/date change during dst causes this problem.

I know it isnt an issue that would normally come up much, but it could be catastrophic on some systems if attempted. A MAN on timezone describes it as a "limitation"! Systems that have time servers updating their clocks regularly must manage this differently I guess.

You can, however, test the november date by changing the hardware clock in the bios temporarily. This test works fine.
It also appears that the bios clock remains 1 hour behind the o.s. time for the duration of the dst interval.
Just fyi.

Thu Mar 8 15:48:46 2007: 2908   jhesswallacehainescom

Am I correct that single quotes ' need to be on either side of the time? Meaning that this: TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00 should look like this: TZ='EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00' That's the way it seems on the man page...Thanks! I just want to get this right so I don't need to buy SCO upgrades...my 5.0.5 works so nicely...

Thu Mar 8 16:50:47 2007: 2909   TonyLawrence

Just look at your current TIMEZONE file..

Thu Mar 8 17:13:56 2007: 2910   jhesswallacehainescom

So if there are 'quotes' presently, then use quotes, otherwise don't?

Sat Nov 7 09:53:00 2009: 7486   asaf

Is there a way to to use some kind of table or script to modify
timezone for many years ahead?????

Sat Nov 7 09:55:22 2009: 7487   asaf

Is there a way to to use some kind of table or script to modify
timezone for many years ahead?????

Sat Nov 7 12:13:12 2009: 7488   TonyLawrence

You are misunderstanding. Unless the daes for DST are changed again, it doesn't need to be modified.

Sat Nov 7 17:54:04 2009: 7489   BigDumbDinosaur

Is there a way to to use some kind of table or script to modify timezone for many years ahead?????

Your question makes no sense. /etc/TIMEZONE only has to be edited one time and the change will be permanent. In the even the Daylight Saving Time rules are changed again, you would edit /etc/TIMEZONE to reflect the new rules. That's all there is to it. Of course, if you are still running a SCO box by then perhaps you should make an appointment with a shrink. <Grin>

Sat Nov 7 18:02:59 2009: 7490   TonyLawrence

if you are still running a SCO box by then perhaps you should make an appointment with a shrink.



Sat Nov 7 18:18:41 2009: 7491   BigDumbDinosaur

I was being kind. <Grin>

Sat Nov 7 18:36:05 2009: 7492   Asaf

I will try to be more clear
in my country the changes between
DST and standrt time are in relations
to religeus holidays so every year it's
diferent date!
I allready implemented a table solution
in a Linux mchine and I wonder if
such a solution can be adopted on SCO??

Sat Nov 7 18:50:16 2009: 7493   TonyLawrence

Why not?

Where do you see the difficulty?


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