UTC Is Enough for Everyone, Right? • Hacker News Board

Re: UTC Is Enough for Everyone, Right?

#281

Post by nwah1 » Wed, May 30, 2018, 3:17 PM UTC

0x0 wrote: post #33

So the article seems to imply you should store all timestamps as UTC (with an additional timezone string ID). But for events in the future that needs to happen on a specific "wall clock point in time", it might be better to actually store the yyyy-mm-dd hh:mm:ss as a string with a timezone next to it, because timezones can and do change often unpredictably. If you pre-calculate what "4.00pm next August 1st" is as a U…

If you had UTC and the original timezone code, you could run a job that updates future timestamps according to timezone changes. This might keep things cleaner.

Re: UTC Is Enough for Everyone, Right?

#282

Post by daveFNbuck » Wed, May 30, 2018, 4:08 PM UTC

mseebach wrote: post #255

daveFNbuck wrote: post #207

Earlier quoted context omitted.

> Google seems to get this right, thankfully. Gets it right for you. If I mean today, I say today. This is especially true when I'm talking to a computer.

Both the words "today" and "tomorrow" ("morrow" being related to the word "morning") are defined in terms of the day, not whether it's before or after midnight. "Noon tomorrow" spoken at 23:55 or 0:05 refers to the same point in time (~12 hours later) in human language. I would argue that "today" is basically unassigned at night - there is no current day in scope. Sometimes we need to use non-human language to commun…

This is how you use today and tomorrow. It's not universal to all human language or even to English speakers. Words have different meanings depending on lots of factors including context and region.

Your definition has the same issue that mine does, just with sunrise being the time around which the meaning of tomorrow is unclear. How high does the sun have to be before "today" becomes defined and the meaning of "noon tomorrow" shifts by 24 hours? If I wake up before sunrise, does tonight refer to now or to after the next sunset?

There's a certain amount of ambiguity inherent to the English language.

Re: UTC Is Enough for Everyone, Right?

#283

Post by LinuxBender » Wed, May 30, 2018, 4:43 PM UTC

My current time is:

1527698540

That seems easy enough for any application to deal with. Perhaps let each app or user convert that back to their ISO 8601 of preference.

Re: UTC Is Enough for Everyone, Right?

#284

Post by tialaramex » Wed, May 30, 2018, 5:06 PM UTC

cryptonector wrote: post #275

tialaramex wrote: post #244

Earlier quoted context omitted.

Wall clocks just track UTC. Today they have leap seconds because we defined UTC to include leap seconds, tomorrow if UTC or a replacement universal time no longer has leap seconds then wall clocks won't have leap seconds.

But then people will notice a few decades later that noon in UTC-minus-leap-seconds is not noon.

But it _is_ noon.

You are probably thinking of sun transit time, "solar noon", the moment in each day when the sun appears to be "highest" in the sky. This varies of course by position on the Earth, it's how people set "noon" when they didn't need to agree with anybody more than a horse ride's distance away what the time was. So, let's say at least 200 years or more ago.

Do you know when solar noon is where you live now? No? Because it's irrelevant. Huge numbers of people live in places where the solar noon changes by an entire hour twice a year for no sensible reason. Does this cause a huge problem? No, there's a slightly elevated rate of road accidents and things like that, but nothing major. A few seconds per decade is _nothing_.

Re: UTC Is Enough for Everyone, Right?

#285

Post by mseebach » Wed, May 30, 2018, 5:15 PM UTC

daveFNbuck wrote: post #282

mseebach wrote: post #255

Earlier quoted context omitted.

Both the words "today" and "tomorrow" ("morrow" being related to the word "morning") are defined in terms of the day, not whether it's before or after midnight. "Noon tomorrow" spoken at 23:55 or 0:05 refers to the same point in time (~12 hours later) in human language. I would argue that "today" is basically unassigned at night - there is no current day in scope. Sometimes we need to use non-human language to commun…

This is how you use today and tomorrow. It's not universal to all human language or even to English speakers. Words have different meanings depending on lots of factors including context and region. Your definition has the same issue that mine does, just with sunrise being the time around which the meaning of tomorrow is unclear. How high does the sun have to be before "today" becomes defined and the meaning of "noon…

Yes, there's ambiguity, but there's no reason to introduce new ambiguity where none existed before by trying to reason about these words in terms of midnight (possibly for the benefit of computers), when that was never where these words were anchored. That was the point I was trying to make.

Re: UTC Is Enough for Everyone, Right?

#286

Post by seanp2k2 » Wed, May 30, 2018, 5:34 PM UTC

caf wrote: post #236

ithkuil wrote: post #235

Earlier quoted context omitted.

> [..] regularly scheduled meeting time specifically to the UK or to the US very funny things happen when there is a shared physical resource e.g. a booked meeting room, and you have a bunch of people schedule meetings with different reference time zones. ah, and if you think this creates havoc only for a the few weeks while the TZs are out of sync, remember that in the southern hemisphere DST is applied in "reverse"

Oh, that's fun: "A change in the definition of a timezone has caused previously non-conflicting bookings to conflict."

Yep, time zones are lame and we’d be much better off if everyone just got used to saying the time in UTC. But then an “9 to 5” would become a “regular 8-hour shift” and be less fun to talk about, school might let out at 0300, and the times would vary when it’s dark / light out, which would probably be too much for the average joe to handle.

Re: UTC Is Enough for Everyone, Right?

#287

Post by JdeBP » Wed, May 30, 2018, 5:44 PM UTC

tlrobinson wrote: post #181

> (My all-time fave is RFC 2606, thanks for asking! I’m in awe of that absolute unit. Where would we be without that banger? We’d be in complete fucking chaos, that’s where.) RFC 2606 ("Reserved Top Level DNS Names") not RFC 2616 ("Hypertext Transfer Protocol -- HTTP/1.1")? I would have gone with the latter. Related: I just noticed Cloudflare's DNS service (1.1.1.1) follows the suggestion in RFC 2606 and resolves *.l…

Enjoy RFC 6761.

Re: UTC Is Enough for Everyone, Right?

#288

Post by aeorgnoieang » Wed, May 30, 2018, 5:50 PM UTC

agumonkey wrote: post #96

akkartik wrote: post #25

"Did you hear about the clock maker who was the first to add a second hand to a clock? His first prototype was a complete failure, but he got it working the second time." Very funny, but here's the real reason ( https://www.etymonline.com/word/second ): > second (n) from Old French seconde , from Medieval Latin secunda , short for secunda pars minuta , "second diminished part," the result of the second division of th…

One of my most visited and favorited website. Donate to the author.

The author's bio is great:

- [bio](https://www.etymonline.com/columns/post/bio?ref=etymonline_f...)

Re: UTC Is Enough for Everyone, Right?

#289

Post by aeorgnoieang » Wed, May 30, 2018, 5:51 PM UTC

masklinn wrote: post #243

erpellan wrote: post #132

Postgres have done a really good job here. It not only understands offsets (which most devs think are timezones) it also understands timezones. What's the difference? GMT-8 is an offset. America/New_York is a timezone. This becomes important when you want to schedule a meeting on the east coast of the USA in April - Europe and the US change DST on different dates. But if you tell postgres you want a time in a particu…

How do you update the tzdb?

It looks like it's embedded in the PostgreSQL source, tho I imagine there's probably also a way to update it without upgrading PostgreSQL itself:

- [postgres/src/timezone at master · postgres/postgres](https://github.com/postgres/postgres/tree/master/src/timezon...)

Re: UTC Is Enough for Everyone, Right?

#290

Post by rspeele » Wed, May 30, 2018, 5:52 PM UTC

seanp2k2 wrote: post #286

caf wrote: post #236

Earlier quoted context omitted.

Oh, that's fun: "A change in the definition of a timezone has caused previously non-conflicting bookings to conflict."

Yep, time zones are lame and we’d be much better off if everyone just got used to saying the time in UTC. But then an “9 to 5” would become a “regular 8-hour shift” and be less fun to talk about, school might let out at 0300, and the times would vary when it’s dark / light out, which would probably be too much for the average joe to handle.

Also depending where you live, it might become the next calendar day in mid-afternoon. Imagine: "Want to meet up Friday?" ... "You mean tomorrow afternoon, or the morning after that?"