Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

nature.com

Post reply on HN
Print view View original

341–350 of 456 posts

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

#341

Post by debugnik »

red_trumpet wrote: post #255
techdragon wrote: post #80

Hot take… Storing anything as UTC was a mistake and we should be using TAI for all storage and computation, only transforming into more human friendly formats for display to end users. This never needed to be a problem except we decided to make it harder to use TAI than UTC and so everything got built up off the backs of legacy bios level hardware supported UTC style clock behaviour, when we should have been using TA…

> we should be using TAI for all [...] computation How do you add a full day, if you do not know whether a leap second occured or not?

The same way you add a full year without knowing if a country will change timezones or vote to drop daylight savings: you distinguish between timestamps and calendar dates, and keep updated your timezone/leap second database.

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

#342

Post by adg001 »

gpvos wrote: post #204
coenhyde wrote: post #143

Earlier quoted context omitted.

You've made a very good point. All new software/systems I build will use TAI64. As an industry we should just push this move ourselves

Libraries are already available. See https://cr.yp.to/time.html and the pages linked from there.

Yep, and here it is one in Erlang – Taider https://github.com/secYOUre/taider

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

#343

Post by 3pt14159 »

codetrotter wrote: post #287
yreg wrote: post #259

Earlier quoted context omitted.

>Sometimes the best solution is not a technical solution (“halt the markets for 15 minutes before/after”) We've had an election recently, right on the day when DST changed. On the night of counting of the votes, the clock went 2:59 AM -> 2:00 AM. To save themselves trouble the Statistics Office instructed all vote counters that under no circumstances are they to enter or update anything in any system during the repea…

The interesting thing about DST is that it's not really repeating the hour, if you include the time zone offset in your time stamp. Here, look. Using the time zone for Norway in this example, with the `date` command on macOS. First the last second before DST ended in Norway this year. TZ=Europe/Oslo date -I seconds -jf %s 1667091599 2022-10-30T02:59:59+02:00 Then the second after. TZ=Europe/Oslo date -I seconds -jf %…

Yes, but not every logger, db, etc is going to include the timezone. What they did was the right call for the situation.

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

#344

Post by zinekeller »

divbzero wrote: post #251
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…

This is a good story regardless, but if you do want to derive some morals from the experience: – Seemingly simple tasks can be more complex than you expect (“add a leap second on this Wednesday”) – Real world systems can be more complex than you expect (“bunch of software I never even knew existed”) – Planning and testing can make a big difference vs. just winging it (“a bunch of our Linux servers had kernel panics f…

– Success can be a non-event that goes unnoticed (”everything worked and no money went missing”)

And yet, there are still Y2K deniers (to be fair some people have exaggerated it to the point that they're promoting it as the end of the world).

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

#345

Post by tim-- »

geenew wrote: post #332
codetrotter wrote: post #287

Earlier quoted context omitted.

The interesting thing about DST is that it's not really repeating the hour, if you include the time zone offset in your time stamp. Here, look. Using the time zone for Norway in this example, with the `date` command on macOS. First the last second before DST ended in Norway this year. TZ=Europe/Oslo date -I seconds -jf %s 1667091599 2022-10-30T02:59:59+02:00 Then the second after. TZ=Europe/Oslo date -I seconds -jf %…

Perhaps another moral to add: ISO8601 solves a lot of problems.

This is a misconception. ISO8601 has six versions, is 14 pages long, and defines way to many ways to represent dates and times.

Everyone should follow RFC 3339.

https://www.rfc-editor.org/rfc/rfc3339#section-5.6

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

#346

Post by 3pt14159 »

jimmaswell wrote: post #190
svara wrote: post #138

Earlier quoted context omitted.

The moral of the story is that laziness is a virtue. Think of all the time that could have been saved, had you had no plans like your partners ;)

Think of all the time that could be better appropriated than on fintech in general. Seems like such a waste of resources siccing a bunch of computers against each other in a zero sum game of stock arbitrage. I will admit some of the stuff tech comes out of it is cool on its own at least.

Eh. I see the downsides of a lot of that HFT stuff, but there are upsides too. Yes a lot of it is zero sum, but not all of it is. Lowering spreads between currencies, say, does materially help non-finance actors. There are other areas of the stock market that are useful too. Ingesting financials and other non-manipulated data to better reflect a company's true worth at any time helps, for example, employee option holders that seek to have a fair renumeration for their labour.

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

#347

Post by Vecr »

a9h74j wrote: post #284
divbzero wrote: post #251

Earlier quoted context omitted.

This is a good story regardless, but if you do want to derive some morals from the experience: – Seemingly simple tasks can be more complex than you expect (“add a leap second on this Wednesday”) – Real world systems can be more complex than you expect (“bunch of software I never even knew existed”) – Planning and testing can make a big difference vs. just winging it (“a bunch of our Linux servers had kernel panics f…

> Sometimes the best solution is not a technical solution I once came across an early 1950s Scientific American article by Bertrand Russel, IIRC. It included a cartoon. Frame one: Computer beats man at chess. Frame two: Man unplugs computer.

How about this? Frame one: man beats woman at chess. Frame two: woman shoots man with automatic pistol. Not sure how deep the original really is if you think about it...

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

#348

Post by 3pt14159 »

techdragon wrote: post #80

Hot take… Storing anything as UTC was a mistake and we should be using TAI for all storage and computation, only transforming into more human friendly formats for display to end users. This never needed to be a problem except we decided to make it harder to use TAI than UTC and so everything got built up off the backs of legacy bios level hardware supported UTC style clock behaviour, when we should have been using TA…

The issue doesn't go away.

> more human friendly formats for display to end users.

This is what's doing the very heavy lifting in your proposal. Leaving aside not knowing when future leap seconds will occur (and thus getting mismatches when broadcasting to different computers that may or may not get the information about the leap seconds at different times) the sheer fact of the matter is that software developers are users too. They will take shortcuts and display TAI as UTC because "something, something people are lazy or uneducated."

We do not need leap seconds. We never should have implemented them. They are a scar on our software for potentially hundreds of years already for any application that seeks to have high accuracy over time.

Time is very frequently a join key or part of a join key in a database and these small differences mean countless hours wasted to investigate "couple of record" mismatches.

Just stop using leap seconds. We will be fine.

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

#349

Post by debugnik »

zokier wrote: post #164
finnh wrote: post #97

> 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. So, in one century, we'll get 1 minute's worth of drift. Recall that we all share the same clock within timezones, and 1 minute of drift between atomic & solar clocks is the equivalent of traveling 1/60th of your…

And of course there are things like Spain being in utc+1 despite sitting almost entirely west of Greenwich.

I can barely wrap my head around the idea of living in UTC when I remember that, my friends and I already feel like the sun sets too soon these days. We're just so used to 9:30pm sunsets during summer!

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

#350

Post by 3pt14159 »

Imagine how we would feel if we adjusted lat-long definitions instead of smearing or leaping time in order to adjust for the slowing down of the rotation of the earth.

Does that sound bananas to you?

Of course it is. That's what we're doing with leap seconds. Only some people smear and some people leap and they don't even do it over the same time or in perfect synchronicity.

Just ditch the leap seconds. They are not worth the cost.

Post reply on HN