311–320 of 466 posts
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This makes me wonder: Should NTP servers broadcast the tz database...? (And should the tz database support a stable but turing-complete scripting/bytecode language?)
That sounds like the beginning of a story that ends with an RCE.
At some point the correct solution is for engineers to collectively agree to refuse to model government-prescribed deviations from convention. Or, put more obliquely, provide more feedback to make it more obvious who is bearing the cost of the complexity of these requirements. It's a social problem and it calls for a social solution. I know, there's a lot of disagreement around where the point in question is, but it…
disagree - good products meet their users where they are and bury complexity under the hood. i can't imagine trying to use a calendar app (or any app really) that refuses to operate in any mode other than UTC.
Also, are the users where they are because they want to be there, or because long ago some government or religious leader forced something through and they go along with it because of some kind of inertia?
The most amusing tidbit about the tz database is that it contains an estimate of Big Bang, and it refuses to calculate timezone transitions occurring before the Big Bang. The commit message at https://github.com/eggert/tz/commit/b22d459a367f4d01b10f6f6b... says: > For example, Glib computes Sao Paulo time stamps as if Brazil's circa-1913 rules were still in effect. (Thanks to Leonardo Chiquitto for reporting the bug.…
Separately, I'm a little skeptical of the tzdb's endeavor of even thinking about pre-Unix-epoch stuff. The bug-to-utility ratio of that stuff doesn't seem to be there. `zic` is where most of the ugly gnarliness of tzdb lies, and I sometimes feel that it would have been better if `zic` weren't an artifact others could depend on.
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Unless the gates need to open at 2:30am and in the case of daylight savings time that hour is skipped.
Not if that cron file (you can have multiple cron files per user/system) is configured to run in the local timezone.
Earlier this year I had to write a function to find the current local time given a US address. The naive way to do so would be via a static mapping of state to time zone but there are a few edge cases that preclude doing this; in the interest of cost and speed relative to this specific application I spent a few dollars on a CSV that maps every US ZIP code to UTC offset and whether DST is followed (among other data).…
> The naive way to do so would be via a static mapping of state to time zone but there are a few edge cases that preclude doing this More than a few, state is really the wrong resolution here, US timezones follow counties and native reservations borders. ZIP codes should probably be good enough but I'd be careful too. If your volume of addresses isn't too crazy, the robust way is to reverse geocode them and use a lib…
County is the smallest resolution one can reasonably use, but in terms of what timezones themselves follow, that would be metro areas. I.E. the Chicago metro area has its timezone and cities (or counties, if you will) that are part of that metro region, even when belonging to other states that largely follow a different time zone, follow the metropolis’ tz instead.
(Not arguing with you but clarifying the meaning of “follow” here.)
Related to the subject, can anyone recommend a book about timezones? Not a technical, programming book, but one with the history of time zones and curious use cases?
https://en.m.wikipedia.org/wiki/Longitude_(book)
It's generally pretty well-regarded and closely related.
The time zone in Palestine is a bit weird as well: https://en.wikipedia.org/wiki/Time_in_the_State_of_Palestine They have DST, but it's not on fixed dates, the government just announces each year when it's going to start and end. Sometimes with less that a week's notice, which must cause all kinds of interesting problems for people.
Without getting deep into politics I don't understand why they would prioritize spending effort on DST at all, seems like there are plenty of other concerns.
Earlier this year I had to write a function to find the current local time given a US address. The naive way to do so would be via a static mapping of state to time zone but there are a few edge cases that preclude doing this; in the interest of cost and speed relative to this specific application I spent a few dollars on a CSV that maps every US ZIP code to UTC offset and whether DST is followed (among other data).…
Nah, the weirdest time zone is Africa/Addis_Ababa, which nobody in Ethiopia follows. Instead the locals offset the time by 6 hours. So the AM cycle starts at dawn (i.e. 6am), and the PM cycle starts at dusk (i.e. 6pm). https://en.wikipedia.org/wiki/Time_in_Ethiopia
FWIW, the English-speaking world used to switch years on March 25: https://en.wikipedia.org/wiki/Calendar_(New_Style)_Act_1750#...
Neither of these are technically things that tzdb can even talk about. They're concerned with civil time, not calendars or other "reckoning" problems.
In my opinion, the best way to see it is not to pretend their are weird timezones. It is not because most of the world do summer time and that when they do they have a 1h transitions that we should take it for granted. This article do not mention the Chatham Standard Time Zone from Chatham Islands archipelago in NZ which is 45 minutes ahead of New Zealand Daylight Time, nor the Central Western Standard Time (Australi…
> It is not because most of the world do summer time Eh? Most of the world don't do summer time.