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Leap Second To Be Added Dec 31, 2008
ammorris writes "Don't be the laughingstock of your friends when you shout 'Happy New Years' a second too early ... The International Earth Rotation and Reference Systems Service has announced that a leap second will be added on December 31, 2008 at 23h 59m 60s, meaning that this year will be exactly one second longer. The last leap second occurred Dec 31, 2005; they are added due to fluctuations in the rotational speed of the earth. You can read all about leap seconds on Wikipedia."
I tried to resist, but I still leapt at the chance...
Gah! I can't take another second of this!
"Kittens give Morbo gas!"
Until 2007 legal time in the US was mean solar time, and that has no leaps, so this is the first leap second for the legal US time. Officially, of course, USNO and NIST were keeping UTC, but that didn't make it legal. The difference shows up in computer time scales.
Uhh, wouldn't it be nice if we were given a little bit more of a warning? Say, something like, oh a week?
You may laugh, but I work in Air Traffic Control. We rely on absolutely precise timing in a system distributed over 1000s of kilometres. Many components can be marked as non-functional by the system if they appear to have an incorrect clock.
Every time we add a leap second we get issues raised. I have to say it is a real PITA.
http://michaelsmith.id.au
No-one ever R's the FA, so the date on the bulletin is completely irrelevant. If it's not in a slashdot summary, we don't know about it.
Yes, yes, that's Nix vs Hedden and it was ruling by the U.S. Supreme Court in 1893. The court ruled that in the common parlance of the time a tomato was seen to be a vegetable and not a "fruit of the vine", working from the assumption that most people at it for a main course instead of a dessert. I think that if you were going to pick up on the ridiculous nature of the case you'd focus on the reason behind the court case — that taxes needed to be paid on imported vegetables and yet not on imported fruit.
XML is like violence. If it doesn't solve the problem, use more.
Those of us in the U.S. will get to celebrate our extra second during a reasonable time of day, as it's in UTC. The local astronomy museum generally has a baloon drop at that time, so that the kids can feel they celebrated New Year's properly.
Bruce Perens.
I work a graveyard shift. You can bet I'll bring this up to the boss. I don't work for free!
If you want news from today, you have to come back tomorrow.
Wait just a second, now! I ... oh.
A truly excellent pizza parlor is a delight unto the heavens. Treasure the sauce and the toppings!
Bush will do anything to remain president just a little longer.
Haven't they heard of NTP? http://en.wikipedia.org/wiki/Network_Time_Protocol
Yes, but we are talking about interfaces between a lot of different networks, each of which have their own GPS based time reference. An NTP daemon in each network talks to the GPS device, but there is no way to be sure that all the daemons will slew the time at the same rate.
http://michaelsmith.id.au
You'll have to hope for a leap-inch or two before that happens
Table-ized A.I.
Yeah, we had problems in Google with these too; we have large networks of machines that used to use multiple different NTP servers (for resilience). Turns out not all NTP servers implemented leap seconds the same way, and many cluster based applications get upset when they aren't synchronized to within 100ms.
Now, we run a dry-run of a fake leap-second with all software a few weeks before the leap-second failover. It's the only way to be 100% sure that applications changed since the last leap second won't have problems. Though, most unittest frameworks now have the ability to implement second skewing, since the suffering caused by the 2005 leap second.
The main problem is that the POSIX description of how to do a leap second is retarded; you basically go from 00:00:00 to 00:00:59, some apps also get upset when they see the same time twice.
John
I'm sorry? Fluctuations in the rotation of the earth? You mean the earth is accelerating and breaking?
Yes, that's exactly what we mean (well, "braking" rather than "breaking"). The earth does not have a constant angular velocity. To conserve angular momentum, as the mass distribution of the earth changes (e.g. due to glacial rebound), the spinning of the earth speeds up and slows down. It also slows down a little due to tidal braking. So a "day", as measured by the rotation of the earth relative to the fixed stars, is not exactly 86400 seconds. It's generally a little more, around 86400.001 seconds at present, and it varies from day to day and from year to year. Now that civil time (UTC) is kept with atomic clocks, this is a genuine problem. Leap seconds are introduced to keep UTC close to UT1 (astronomical time).
It has nothing to do with the fact that a rotation around the sun is not exactly 365.25 rotations around our own axis? hmm...
That's right. Leap seconds have nothing whatsoever to do with that. They don't affect the calendar. That's what leap days are for. Leap days keep the calendar in sync with the seasons (by setting the average calendar year length to 365.2425 days, very close to the vernal equinox year which is currently 365.242374 days).
Some people mistakenly think NTP is a silver bullet for handling timing issues.
NTP is great for keeping consistent time *over time*. It is horrible for handling stuff like a leap second, it simply takes too long.
Some systems use GPS, some use IRIG-B and some use NTP. Some handle leap seconds and some don't.
If you work with telemetry, like I do, you need time to be 100% correct all the time or else the data is worthless. This leap second is actually causing NASa and other space agencies to not do satellite supports close to midnight on new-years eve UTC.
The UTC second 60 gets added at midnight only at those locations where UTC == local time, i.e. places like England.
For us in the rest of Europe, the leap second will be added an hour after local midnight, i.e. at 01:00:60 CET.
Terje
"almost all programming can be viewed as an exercise in caching"