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Timezones, Daylight Savings, etc... - brad's life — LiveJournal [entries|archive|friends|userinfo]
Brad Fitzpatrick

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Timezones, Daylight Savings, etc... [Jul. 7th, 2000|12:46 am]
Brad Fitzpatrick
Family just got back from the casino ... they're all up $20-$30 bucks, except for my dad: he's down $3.

I've been researching time zones, daylight savings time, and related things the past 3 or 4 hours. Lot of reading, a little coding. Very interesting (yet extremely confusing and unnecessary) stuff.

I still love Swatch's Internet Time (aka "World Time"). When it first came out I thought it'd certainly flop, but it seems to have caught on quite well. No, it's not pervasive yet, but I'm going to help ... I'm going to make available the Internet time in the LiveJournal style system, and probably make the WorldTime be present alongside all other date entries once timezone support comes along and users can choose which of 1 or more times to show --- author's time, user's time, and/or WorldTime.

Fun time fact: GMT (Greenwich Mean Time) is a time-zone (European) that sits on the universal time zone UTC, standing for Universal Time Coordinated. Dumb acronym? Yes, on purpose. The English wanted CUT (Coordinated Universal Time). The French wanted TUC (Time Universal Coordinated (in French, of course)). The compromise? Mix it up so neither make sense, of course... hence, UTC. Interestingly, the same thing happened with the packet sizes in ATM technology: The Japanese have a small country where latency in phone circuits was never an issue, so they didn't have echo cancellation circuits. Naturally, they wanted small (32-bit) packets. The US already had echo cancellation filters everywhere, so they wanted more bandwidth .. 64-bit packets. The classic latency vs. bandwidth trade-off is this: if you have small packets, you have more framing information being sent than real data, but you have to wait for awhile (until the end of the packet) to actually use the information. The commitee faught back and forth until they decided on 54-bit packets... 48 bits and a header, if I recall. Can current systems hold that efficiently? Not really. Pretty retarded. Probably why ATM was so damn slow to catch on... high costs to develop all the supporting hardware and software. I hate it when committees design crap without a reference implementation first. Grrr... </RANT>.

Anyway, back to time-zone stuff ... there are tons of timezones, not just on hour boundaries, but on half-hour boundaries as well. And there are different named timezones and TZ codes within the same UTC offset (e.g. -0800) because they represent different daylight savings time characteristics: Arizone, for instance, does not observe DST, yet the other states in that TZ offset do. Totally confusing. And in Africa, one country observes it, the rest don't. In Europe it's scattered. Russia does. South America doesn't. And each one begins them at different times. Australia just very recently changes all theirs around (when they start/end). The idea (thanks to Benjamin Franklin, it turns out) is to make people and the economy more efficient by getting us to get more work in during the day. Why can't we just change our sleeping schedule? Instead of setting our entire country's clocks back, can't we set our alarms back? Totally retarded.

Okay, I'm going back to reading more stuff. It's all very interesting, but at the same time I can't help but think things would be better off had it been kept simple.

[User Picture]From: d4b
2000-07-07 07:56 am (UTC)

as if 30 and 15 minute divisions were bad enough...

The last time I checked (and this is unfortunately something like over ten years ago) there are (were) a few places (Saudi Arabia?) which use even thinner slices than 15-minute divisions. Check out the timezone files in Unix for a whole ton of rules and special cases.

Like I said, you'll actually make your life easier if you ignore the issue altogether: Let the Journal-holder set the posting's time however their local machine sets it (and allow them to overwrite the time to do things like back-dating). Use this only for display (and maybe the calendar view). Then order everything in the views based on post time (as determined by the database server).
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[User Picture]From: bradfitz
2000-07-07 12:32 pm (UTC)

Re: as if 30 and 15 minute divisions were bad enough...

That's what I already do. But there are problems with that. :/
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[User Picture]From: perdurabo
2000-07-07 10:30 am (UTC)

I love your tag...can I use it? :-)
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From: itchi
2000-07-07 05:25 pm (UTC)
I've heard that Franklin was an insomoniac. And not being able to work at night because of the whole lack of lightbulbs was a major drive in his research of electricity. Interesting tidbit especially when combined with the time zone thing I didn't know about. A pioneer of sorts, workaholic, or genuine geek who liked to stay up all night and work on projects.. sound a little familiar?
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[User Picture]From: zaiah
2000-07-08 04:33 am (UTC)

Re: Franklin?

That night time research being when poor Richard wasn't out womanizing? How many illegitimate children did this man have anyway? and know what? were I there in his day.. hell even when he was old - I would have volunteered to test drive him.. what a guy.

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[User Picture]From: cryo
2000-07-08 01:15 pm (UTC)
ok, so what's the hold up before we see the @400 next to the timestamp? :)

My test php is:

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