No and they shouldn’t be. Leap seconds were never a great idea and they become an increasingly worse idea with every passing year. They are a great example of a standards making decision made without sufficient negative feedback from its implementation costs.
Ask HN: Are systems ready for the first negative leap second?
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Re: Ask HN: Are systems ready for the first negative leap second?
#72You may be relived to know that Unix epoch time does not have this problem. But you may also be horrified to know why. First, epoch seconds are not the numbers of seconds since 1970/01/01. This is a lie we tell to children. Rather, epoch seconds are the number of days since 1970/01/01 * 86400 plus the number of seconds since midnight. Leap seconds, to epoch time, don't exist. Or maybe they are double counted. Or mayb…
Indeed. I like to say, we would like three things to be true: 1) Every day has 86400 seconds. 2) Every day is from noon (sun exactly above) to noon (sun exactly above). 3) We use SI seconds. You can't have all three. Pick any two: 1, 2, not 3: What you describe. Day has 86400 seconds, we keep in sync with the sun, but we tweak the seconds a bit. There are different versions, like epoch time, or UT1. 1, not 2, 3: Ever…
The length of a noon-to-noon day (synodic day) varies from +29.9 seconds near the winter solstice to −21.3 seconds near the autumnal equinox[1]. If you account for the seasonal changes, you get closer to the ideal solar day which only deviates by milliseconds from 86400 s, but that deviation does pile up and "forces" leap seconds. I say "forces" because it's a legal requirement that the time tracks the sun.
Going to leap hours I think is a sufficient kick of the can down the road, one is only needed every few centuries. Pretty sure something'll happen in the next 600 years that obviates the need for that though (nuclear war, asteroid, technological singularity, need for a unified solar system time...), so us hack programmers can assume all three of those things.
Re: Ask HN: Are systems ready for the first negative leap second?
#73Earlier quoted context omitted.
Indeed. I like to say, we would like three things to be true: 1) Every day has 86400 seconds. 2) Every day is from noon (sun exactly above) to noon (sun exactly above). 3) We use SI seconds. You can't have all three. Pick any two: 1, 2, not 3: What you describe. Day has 86400 seconds, we keep in sync with the sun, but we tweak the seconds a bit. There are different versions, like epoch time, or UT1. 1, not 2, 3: Ever…
The length of a noon-to-noon day (synodic day) varies from +29.9 seconds near the winter solstice to −21.3 seconds near the autumnal equinox[1]. If you account for the seasonal changes, you get closer to the ideal solar day which only deviates by milliseconds from 86400 s, but that deviation does pile up and "forces" leap seconds. I say "forces" because it's a legal requirement that the time tracks the sun. Going to…
Legal only in the sense that the requirement hasn't changed since the Romans invented the concept of time.
If you really want to think about it, were it not for them, we wouldn't have many of the things we have today.
Philip K. Dick was correct, the Roman Empire never truely fell.
Re: Ask HN: Are systems ready for the first negative leap second?
#74[flagged]
Re: Ask HN: Are systems ready for the first negative leap second?
#75Earlier quoted context omitted.
Explain why negative leap seconds are worse? Intuitively it seems like normal leap seconds would cause way more issues, or at least not more.
I am not an expert in Time systems but I imagine the problem is similar to daylight savings problems. With a leap second it's like putting the clocks forward an hour. With daylight savings, In your time series database you suddenly go from 0059 to 0200. 0100-0159 are missing, but that's fine. Most systems are fine with missing data, because we assume there will be occasional outages and such When you go the other dir…
Negative leap seconds mean we skip a second, normal leap seconds are the ones where we repeate a second.
Re: Ask HN: Are systems ready for the first negative leap second?
#76Earlier quoted context omitted.
I once worked with smart meters for electricity consumption that do run 24/7. Leap seconds were not an issue but we had a very similar one now that I think about it: DST shenanigans! Like how much time is there between 2 and 3 am? Usually one hour, but sometimes 2 and also sometimes 0. It looks simple at first but it creates a lot of edge cases that your business logic now needs to handle and we had a fairly complex…
I can relate: My son is born at 02h30 right DST change time. It tooks 3 f*cking days to get his birth registered in the Hospital new birth registration system. The hospital (at the time) just got digitalized and most systems where not able to agree if he was born after or before DST changes. PS: I guess he is born fated to be a software QA later on.
This commenter says he has different birth dates in different countries' sytems, which is correct if you consider the exact time of birth, but... that's probably a bug? https://news.ycombinator.com/item?id=48853128
Re: Ask HN: Are systems ready for the first negative leap second?
#77I wonder how many systems actually care? I presume the core NTP servers handle this well, and most systems just feed off of that? GPS satellites probably handle it well too, but maybe some consumer or even industrial GPS receivers don't? Maybe some trading systems? I don't think crypto systems care too much.
I wonder if there's things that run 24/7 and need to be monitored.. e.g. if you have oil flowing through some pipeline at 100 liters/second, one particular minute will have 6100 liters, and someone will want to get paid for that 100 extra liters. But the meter/reporting tool would say "Well, we measure every second, and the meter reported a constant rate of 100 liter/second, and as we know we have 60 seconds in a min…
No matter what the 100 liters of mystery fluid are worth, if the pump is running continually, the billing for that day would only be off by .0011574%, so either side can probably afford to absorb the loss.
Though if it's valuable enough it could of course be "worth" paying top dollar to have engineers solve a ludicrous non-issue.
Re: Ask HN: Are systems ready for the first negative leap second?
#78Fortunately, in the past couple months, the likelihood of actually needing a negative leap second in the next few years has been trending down. This is based on measurements and predictions done by the IERS, the data for which they publish weekly in their Bulletin A [0]. I've been tracking this data for a while, and their DUT1 predictions have been trending more negative over the past few months, suggesting that the anticipated negative leap second is likely to be delayed, or it may very well not happen at all.
[0] https://datacenter.iers.org/data/latestVersion/bulletinA.txt
Re: Ask HN: Are systems ready for the first negative leap second?
#79Earlier quoted context omitted.
Indeed. I like to say, we would like three things to be true: 1) Every day has 86400 seconds. 2) Every day is from noon (sun exactly above) to noon (sun exactly above). 3) We use SI seconds. You can't have all three. Pick any two: 1, 2, not 3: What you describe. Day has 86400 seconds, we keep in sync with the sun, but we tweak the seconds a bit. There are different versions, like epoch time, or UT1. 1, not 2, 3: Ever…
The length of a noon-to-noon day (synodic day) varies from +29.9 seconds near the winter solstice to −21.3 seconds near the autumnal equinox[1]. If you account for the seasonal changes, you get closer to the ideal solar day which only deviates by milliseconds from 86400 s, but that deviation does pile up and "forces" leap seconds. I say "forces" because it's a legal requirement that the time tracks the sun. Going to…
> Going to leap hours I think is a sufficient kick of the can down the road, one is only needed every few centuries.
The drama of rolling out the Gregorian calendar to replace the Julian so that the seasons went back to where they 'should' be shows how convoluted things could get in coördinating things.
Re: Ask HN: Are systems ready for the first negative leap second?
#80Earlier quoted context omitted.
Suppose being charged by time used to run your tasks. Then your task takes -1 second, you will be charged zero, 1 second, or 18 quintillon seconds?
If you're calculating time that a task took by subtracting two UTC datetimes instead of just using a monotonic timer or at least unix timestamps, you're doing it wrong either way
If systems are not ready, then there is plenty of room of systems doing it the wrong way.