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You Can Look Forward To 8 More Years of Leap Second Problems (cio.com)
itwbennett writes: As previously discussed here, the World Radiocommunication Conference (WRC) met "for nearly the entire month of November, and one of the hot-button issues [was] what to do about the leap second." But, as they did at the 2012 conference, the WRC voted to postpone the decision — not just until the next WRC in 2019, but until the one after, in 2023, while the International Telecommunication Union conducts further studies into the impact of tinkering with the definition of Coordinated Universal Time.
It's never given me any problems.
Then again, I'm not the kind of person who writes my own date/time validation routines because daylight saving is part of Agenda 21 and fluoride causes autism. I suspect it's them making most of the noise.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
See, the problem is most people don't understand where our system of time keeping comes from or why it's important.
The reason we adjust for leap years and leap seconds is our calendar is a close approximation to our orbital period ... but it's not exact.
At noon, on the day of a solstice or an equinox, the sun is in a known position in the sky. We use it for important things like navigation and timekeeping, and knowing when the hell things like eclipses, sun flares, high tides, and comets might happen ... or that asteroid which might kill us.
It's a real physical property, which we kind of need to keep track of. It's NOT some thing you can say "oh, well, what does it matter if you're off by a couple of days?".
Lost at C:>. Found at C.
Actually, it doesn't. ntpd, the canonical implementation, doesn't follow the RFC for NTP. Other implementations do the same thing, simply because they're expected to be compatible with it. It does special handling for leap seconds (beyond simply advertising when they occur, so the OS can handle them properly). NTP isn't supposed to do anything with leap seconds, it's supposed to simply count seconds in an epoch. RFC 5905 says it's supposed to count seconds with a "monotonically increasing" UTC timescale.
ntpd doesn't do that - when there's a leap second it counts backwards (or stops counting for a second, depending on how you think of it) in violation of the RFC, and then simply forgets about the leap second. It has the same fundamental flaw as POSIX.
"National Security is the chief cause of national insecurity." - Celine's First Law
We use it for important things like navigation and timekeeping, and knowing when the hell things like eclipses, sun flares, high tides, and comets might happen ... or that asteroid which might kill us.
I'm a professional astronomer, who occasionally needs to time things to sub-second precision over multiple years - and the leap second is, to me, nothing but a pain in the arse. Let's run down your list:
* "navigation" - No one navigates by the sun and stars any more - at least, certainly no one who needs sub-second precision.
* "timekeeping" - Atomic clocks keep time irrespective of the sun.
* "eclipses" - Eclipses don't care whether the sun's at the meridian or not: they only care about the relative position of the sun and the moon, which you can calculate perfectly easily with an arbitrary time standard.
* "sun flares" - Solar flares don't care whether the sun's at the meridian or not.
* "high tides" - The sun makes a small contribution to the tides (which are dominated by the moon), so the leap second *does* help you keep track of this contribution - but who the hell needs to know the high tide to the nearest second?
* "comets" - Comets don't care if the sun is at the meridian or not.
* "that asteroid which might kill us" - That asteroid doesn't care if the sun is at the meridian or not - but there *is* a chance that someone might miscalculate its orbit and not realise that it's going to kill us, because there was a bug in their code dealing with leap seconds.
So, this is something that genuinely puzzles me: who actually *wants* leap seconds? You seem to think that I should want them, but I certainly don't.
So just don't use UTC. The POSIX group only said "UTC" instead of "GMT" because they didn't know they difference and they thought saying "UTC" made them sound cooler. A lot of companies put it in their specs for the same reason. They're all like "Ooo we're all technical because we're using UTC!" Then you ask them if they're really using UTC or GMT and they ask you what the difference is. The only people it really matters for is NASA, and they convert from a well known time system to another well known time system as they need to. Most programmers just need to know the number of seconds since Midnight, Jan 1, 1970, GMT, as God intended.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
I may be mis-remembering, but it seems like a summer or 2 ago, there was a day with 2 leap seconds in it.
Not possible. The leap second committee folks have a mandate never to let the difference between the UTC and UT1 (mean solar time) readings exceed 0.9 seconds. They usually decide to apply a leap second whenever the difference between UTC and UT1 approaches 0.6 seconds. Furthermore, they can add a leap second at the end of any month, although there is a preference for June and December and a second preference for March and September. For there to be two leap seconds in a day, something catastrophic would have had to have happened, like California sliding into the ocean, the Yosemite supervolcano blowing, or the Maple Leafs winning the Stanley Cup.
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