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May 19th, 2005

Israeli time zone woes

Filed under: Israel, Technology — arikb @ 2:38 pm

A coworker asked me about time-zone today:

Subject: Our special time zone: Jerusalem 2005

This is causing problems.

When I invite someone from a different office to a meeting, he receives the meeting time one hour earlier than what I write.

And my answer to that:

That’s not because of our unique timezone. The only thing ‘unique’ about it is that it will switch back to non-daylight saving automatically.

There are two ways to deal with DST in Israel.

  1. Shift your clock one hour forward.
    Advantage: All future and past metings are aligned correctly.
    Disadvantage: You’re not working with UTC, so you can’t sync with NTP anymore.
  2. Change your timezone.
    Avantage:That’s the way to do it. The entire world does it and it works well, except for Israel. It keeps you on UTC, so you can send meetings to the rest of the world and they’ll be okay. Disadvantage: in Israel specifically, the dates for the time-zone change change every year, so you need to readjust it manually, hence the creation of our Jerusalem 2005 timezone.

What you are encountering is a case when you send an invite from a computer with a correct UTC (yours) to a computer with a shifted UTC (for instance Cellcom). Appointment setting is always done in UTC (so you can set up international appointments) but the other system’s UTC is different than yours, so it sets a different time. It is inevitable.

If we would have switched to a shifted-UTC scheme (which is, IMO, a bad thing) the particular company you’re working with will be okay, but companies that work with the time-zone method will get the appointment an hour early. It’s a bloody mess.

I hope this clears things up.

• • •

8 Comments »

  1. You have the “Modified Israeli time zone to allow DST according to those crazy knesset antics” ?
    I heard that it exists, but everytime I get to a windows computer (about once every few months) I can’t seem to find it.

    Comment by Oded — May 20th, 2005 @ 8:56 am
  2. Oh, I just make my own, every year. Microsoft have a tool called TZEdit which lets you create a time zone and modify it. Then I take the relevant registry entries from my registry and distribute it to people (in my company we use a logon script).

    – Arik

    Comment by arikb — May 20th, 2005 @ 2:02 pm
  3. Can you be preseuaded to distribute it?

    BTW - the theme is ok, but the green links don’t do it for me.

    Comment by Oded — May 21st, 2005 @ 11:44 am
  4. I have a better idea.

    Shachar Shemesh has put up some files that can be used for the next few years on his company’s support page (LinGNU), so try them for size. If they do it for you, I’d like to know, I’ll start using them. They’re supposed to be good forever (as long as they don’t change the rules again, which can happen as soon as next year)

    – Arik

    Comment by arikb — May 21st, 2005 @ 2:41 pm
  5. Oh, I needed a color that will be visible on a blue background, on a white background and on a light-blue background. I tried variants of red but they were even worse. If you have a better idea, tell me.

    – Arik

    Comment by arikb — May 21st, 2005 @ 2:43 pm
  6. If you mean - “cornflower blue” (the bg of the comments), then how about this interesting idea: dark gray or dark blue.

    Also - when you edit new posts, I see you have an “upload button” - how can I set on for me as well ? I tried enabling “advanced controls, but it doesn’t appear to do anything (I’m using WordPress from SVN).

    Comment by Oded — May 21st, 2005 @ 6:22 pm
  7. There is also a link where it says ‘X comments’ which background is navy blue.

    Well, I just set up the upload function from options/misc, and set up a minimum level for uploads.

    Comment by arikb — May 21st, 2005 @ 8:17 pm
  8. ftp://ftp.cs.huji.ac.il/pub/tz/israel

    This site is hosting Israeli time zone information files up to date with the latest “crazy knesset antics”. Support is provided for several operating systems including Windows, Mac, Linux and and several Unix flavors.

    The Windows files are .reg files you can double-click to add them to the registry. One file per year.

    Comment by Oren Tirosh — June 20th, 2005 @ 6:11 pm

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