I’m talking about time as represented by, say, your watch, and I’m talking about it in context of internationally agreeing on time.
You think about time and it’s no big deal, right? Twice a year we have to change our clocks for some insane reason which has to do with farmers milking their cows or something, and we all do it, right?
And by the way, it’s Daylight Saving not Daylight Savings which I used in everyday conversation (well, at least twice a year) until about two years ago when I did some research on the subject.
The hard part is understanding the politics of it. Arizona doesn’t honor daylight savings… er… saving. Parts of Indiana honored it for a while, and parts didn’t.
Europe has what’s called “Summer Time” but the dates are different than our dates. Likewise Australia (or New Zealand, I forget) has their own daylight saving dates and it’s flip-flopped (as when it’s Winter here, it’s Summer there…) so they fall back in the spring, and spring forward in the fall…
You get the point.
In short, when we store the conversion time when someone purchases something we store it in UTC, or Coordinated Universal Time, a.k.a. Greenwich Mean Time, a.k.a. what time it is right now in Greenwich. And not the rich suburb of New York Greenwich, but the original Greenwich in the UK.
Note, they don’t change the clocks ever in Greenwich, which is a very nice thing. (Actually, they might but for your and my purposes, they don’t.)
And why it’s not “CUT” is, I believe, because UTC is French, or something.
So, how do I convert that to local time for you? What if I’m looking at times for, say, a whole year?
Here’s what you would need to do to convert a time:
- First off, what country are you from?
- Now, what year is it?
- Now, what dates do the times change this year? Look that up.
- Now, does the time we want to convert fall within the daylight saving range or not?
- Change times prior to the “Daylight Saving” by, say, X hours, and the times after the “Daylight Saving” by X+1 hours.
- And realize that you reverse this before/after thing in Australia.
I guess my point is that, like geography, Time is fraught with politics. In 2007, (based on a law passed in 2005) Congress changed the dates when Daylight Saving time occurs to expand its reach. Even a multi-billion dollar company like Microsoft can’t get the time right.
When you think about Swatch Internet Time from a development perspective, simplicity is definitely a feature.