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The leap second’s time is up: world votes to stop pausing clocks

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Re: The leap second’s time is up: world votes to stop pausing clocks

#121

Post by rkagerer »

hoytech wrote: post #103

In 2015 I was working at a "fintech" company and a leap second was announced. It was scheduled for a Wednesday, unlike all others before which had happened on the weekend, when markets were closed. When the previous leap second was applied, a bunch of our Linux servers had kernel panics for some reason, so needless to say everyone was really concerned about a leap second happening during trading hours. So I was assig…

Here, have a bright shiny imaginary internet point. It doesn't nearly do justice but thanks in any case for sharing your story.

Re: The leap second’s time is up: world votes to stop pausing clocks

#122

Post by dangero »

Google does "leap smearing" which seems like the best human solution to this problem: https://googleblog.blogspot.com/2011/09/time-technology-and-...

standardizing leap smearing algos and constants could work

-Bottom layer is atomic clock seconds -We define targeted relationship between current UTC and atomic counter that will occur on a given day and time X -Time is interpolated to drift UTC into place by the given day and time X -Standards body can adjust time on some regular basis by its relationship to the atomic clock and publish the algo to convert from atomic to UTC

Re: The leap second’s time is up: world votes to stop pausing clocks

#123

Post by N19PEDL2 »

bewaretheirs wrote: post #47
throw0101a wrote: post #9

> How, and whether, to keep atomic time in sync with Earth's rotation is still up for debate. […] > The CGPM — which also oversees the international system of units (SI) — has proposed that no leap second should be added for at least a century, allowing UT1 and UTC to slide out of sync by about 1 minute. But it plans to consult with other international organizations and decide by 2026 on what upper limit, if any, to…

The drift is sufficiently slow that you can fix it with a "leap hour" when needed -- perhaps once every five thousand years. This could be handled for civil/local time via an adjustment in the timezone definitions (something which happens a few times a year today), leaving the underlying UTC timebase unchanged.

Then let's skip the leap hour too: just let UTC and UT1 diverge up to 86400 seconds and compensate that by changing the time zones when needed. Then, when the drift reaches 86400 seconds, the clock times are aligned again. At this point we just need to re-align the dates too, and this can be done by skipping February 29 on a leap year (which should be quite easy to implement in software).

Re: The leap second’s time is up: world votes to stop pausing clocks

#124

Post by jll29 »

There has been a proposal in the 1950s to the UN by a German mathematician to replace the current calendar by a decimal-based system, in which leap YEARS are not needed either: everything would be divisible by 100. I can't remember where I heard this from, but the anecdote goes he got a reply saying thanks for the proposal, but it is not feasible to introduce such a massive change globally, irrespective of the proposed improvements.

Re: The leap second’s time is up: world votes to stop pausing clocks

#125

Post by School-Cotton »

adamsb6 wrote: post #50

Currently software has to be built to accommodate leap seconds. They happen frequently enough that you'll find out within a few years whether your software breaks when time suddenly skips forward or backward. If we kick the can down the road such that eventually we'll need to add a leap minute, we're going to end up with software that was never written to expect time to change in such a way, hasn't had a real world t…

Why would we ever need a leap minute? Just let time zones drift. Unless you happen to be at the exact longitude for which your time zone is correct, the sun's not at its highest point in the sky for you at exactly noon anyway.

Eventually, thousands of years from now when time has drifted by an hour or more (assuming modern technological civilization even still exists by then), each jurisdiction can just change their time zone's offset from UTC, without coordinating with anyone else. Jurisdictions making time zone changes is a well-understood situation that we already know how to deal with.

Re: The leap second’s time is up: world votes to stop pausing clocks

#126

Post by ender341341 »

LaputanMachine wrote: post #111
ender341341 wrote: post #89

Earlier quoted context omitted.

Why have them at all? how many people do things where they actually matter? at the current rate it'll be ~9000ad before we hit an hour offset, and we do hour offsets twice a year, so if an hour off is okay why is 1 second off not?

> we do hour offsets twice a year, so if an hour off is okay why is 1 second off not? The actual Unix time does not change when the clocks are switched between daylight saving time and standard time. Only the time zone changes. When a leap second occurs, the actual Unix time changes, which can lead to bugs, e.g. when a positive time difference comes back as negative. To prevent such issues, a monotonic clock can be u…

Edit: OK, just re-read some docs, looks like POSIX chose the worst of all options and decrements the timestamp experiencing the same second twice...

Wrong info from before edit: Unix time doesn't change either, it's the number of seconds since 00:00:00 UTC on 1 January 1970, though systems may or may not ignore that and set it to match the UTC time.

Re: The leap second’s time is up: world votes to stop pausing clocks

#127

Post by zokier »

ender341341 wrote: post #94
spiderice wrote: post #86

Earlier quoted context omitted.

What would using TAI solve exactly? I'm unfamiliar.

TAI is monotonic clock, and isn't adjusted for solar time of day, it could be considered universal as TAI would be the same between any 2 points, but UTC is adjusted for earths rotation, so a theoretical mars UTC would end up out of sync with earth UTC. EDIT: info below is incorrect about UTC not being monotonic, as pointed out in thread but is useful for monotonic vs non-monotonic: In UTC you can jump forward or bac…

I'm pretty sure UTC is monotonic too, its unix timestamps that really are the true mess

Re: The leap second’s time is up: world votes to stop pausing clocks

#128

Post by zimzam »

adamsb6 wrote: post #50

Currently software has to be built to accommodate leap seconds. They happen frequently enough that you'll find out within a few years whether your software breaks when time suddenly skips forward or backward. If we kick the can down the road such that eventually we'll need to add a leap minute, we're going to end up with software that was never written to expect time to change in such a way, hasn't had a real world t…

Why bother? A calendar year is 365.242 days long... time is already off by about 3/4 of a day the year before a leap year, what does adding a second here or there really do?

Re: The leap second’s time is up: world votes to stop pausing clocks

#129

Post by ender341341 »

rightbyte wrote: post #100
ender341341 wrote: post #89

Earlier quoted context omitted.

Why have them at all? how many people do things where they actually matter? at the current rate it'll be ~9000ad before we hit an hour offset, and we do hour offsets twice a year, so if an hour off is okay why is 1 second off not?

Ok let future generations take the hit. Got ya. Selfish ...

How big of a hit is it on the future generation, they can just change their DST, which already happens every few years anyways?

Re: The leap second’s time is up: world votes to stop pausing clocks

#130

Post by Stupulous »

throw0101a wrote: post #110
ender341341 wrote: post #89

Earlier quoted context omitted.

Why have them at all? how many people do things where they actually matter? at the current rate it'll be ~9000ad before we hit an hour offset, and we do hour offsets twice a year, so if an hour off is okay why is 1 second off not?

> at the current rate it'll be ~9000ad before we hit an hour offset And the leap year problems of the Julian calendar weren't a problem… until they were. And then good luck coördinating things: * https://en.wikipedia.org/wiki/Gregorian_calendar#Adoption_by... * https://en.wikipedia.org/wiki/Adoption_of_the_Gregorian_cale...

The Julian Calendar was good enough for centuries after the empire that invented it had fallen, which I think counts as good enough in general. That said, I'd love to read a story about tracking down some time bug a million layers of abstraction down from the state of tech in 9000AD.
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