U.S. Moves to Kill Leap Seconds

blacklite001 writes "Not content with merely extending Daylight Savings Time, the U.S. government now also proposes to eliminate leap seconds, according to a Wall Street Journal story. Their proposal, 'made secretly to a United Nations body,' includes adding 'a "leap hour" every 500 to 600 years.' Hey, anyone remember the last bunch of people to mess with the calendar?"

now correct me if im wrong

but it seems to be working perfectly fine as it is, why fuck with it?

Apparently not...

According to TFA, it isn't working perfectly fine:

But adding these ad hoc "leap seconds" -- the last one was tacked on in 1998 -- can be a big hassle for computers operating with software programs that never allowed for a 61-second minute, leading to glitches when the extra second passes. "It's a huge deal," said John Yuzdepski, an executive at Symmetricom Inc., of San Jose, Calif., which makes ultraprecise clocks for telecommunications, space and military use.

On Jan. 1, 1996, the addition of a leap second made computers at Associated Press Radio crash and start broadcasting the wrong taped programs. In 1997, the Russian global positioning system, known as Glonass, was broken for 20 hours after a transmission to the country's satellites to add a leap second went awry. And in 2003, a leap-second bug made GPS receivers from Motorola Inc. briefly show customers the time as half past 62 o'clock.

"A lot of people encounter problems with their software going over a leap second," said Dennis D. McCarthy, who drafted the U.S. leap-second proposal while serving as the Navy's "Director of Time."

Now, I can't say that I completely understand why resetting a clock should be so complicated, but it seems to cause problems...

Re:Apparently not...

So instead of letting private companies eventually wise up and write their software to take into account/be able to deal with leap seconds, let's fuck with the entire way we measure time on a global scale. Way to go government.

Re:Apparently not...

Resetting the clock is not complicated, but the current system means there is a 61st second in a minute, as your quote of TFA mentions. People -- including software developers -- are strongly used to dealing with 60-second minutes, and software sometimes makes that assumption. It just requires attention (sometimes a lot of attention) and extra code (sometimes a lot of extra code) to get it right, but since very few people pay attention when a leap second happens, bugs are easily overlooked.

Since leap seconds are based on changes in the time period of Earth's rotation (the sidereal day), and the decay is both very slow and influenced by hard-to-predict factors, leap seconds are not reliably predictable. They can only be announced when they are necessary -- and so it is easy for the displayed time to drift if a leap second announcement is missed or ignored.

Leap hours, though, are different beasts. Virtually every piece of software in the world that displays time knows how to deal with the hour jumping forward or backward. That transition happens predictably and affects a huge number of users, so errors are easily noted.

Re:Apparently not...

But the hour WON'T "jump forward or backward an hour". You'll either have a 23-hour or 25-hour day, plus it will only happen once every 500 years or so. When are you going to test it? When are you going to start putting it into programs? And you thought that programmers storing only 2 digits for the year were stupid and shortsighted...

The whole thing is a crock. Software that hardcodes in conversions between days/hours/minutes/seconds, AND needs to be so accurate to the rest of the world that it has to account for leap seconds, must be rewritten to use a standard library routine. Internally, it should simply keep a seconds counter, and base all intervals off of that. There's no excuse for doing it wrong, and code that does do it wrong should be rewritten if it is critical.

Network Time?

From article:
But adding these ad hoc "leap seconds" -- the last one was tacked on in 1998 -- can be a big hassle for computers operating with software programs that never allowed for a 61-second minute, leading to glitches when the extra second passes.

Why would anyone need to set a 61-second minute to account for leap time other than the guys at NIST in charge of the official time? Just set all your computerized clocks to network sync. We have a network time server that re-syncs itself ever hour and then everything else checks that occasionaly. I've never had to do anything about a leap second except maybe be off by a second for a few hours until time resets itself...

That 0.01% of businesses that require absolute perfect time need to hire better software programmers rather than fscking with how we define time.

"OMGZ! Motorolla screwed up in 2003, and some Russians did the same in 1997! Let's pass a law to protect them!!!"
--
Don't fight Firefox! Let FireFox fight YOU! [bobpaul.org]

Re:Die - leap seconds - Die!

>> you can't predict ahead of time when they will happen.

WHy would you need to guess when? surely the seconds are added at arbitrary points as required, but I can't imagine it is done with no warning.

>> Imagine you make a very precise schedule in advance (e.g. scheduled events on a spacecraft) and then a leap second is announced and everything is then off by a second.

The industry I working does use highly complex systems where precise timing is critical. I can tell you from experience that you have to design for timing errors. They happen, not if but when.

Besides, assuming you've got a system that requires real-time function and accuracy to the second, why would you sync to outside time for anything but maintenance? Keep your timings relative to the system itself. Then you just need to worry about internal clocks...

Re:Apparently not...

That won't work in applications where countrywide synchonization with a precision in fractions of seconds is needed, such as some same-frequency-broadcasts or GSM networks. On the other hand, those probably already have real solutions for this problem, instead of a kludge.

Bingo. You mean synchronization with precision like that which has been used for decades by the telco's (read: ITU jourisdiction). This is a problem what isn't one. Time is relative (sorry, couldn't resist.) I can't believe anyone, let alone Naval Observatory dude thinks in terms of sync to, essentially, a wall clock. That's why internal clocks are used. The time representation for someone looking at the 24 hr clock is simply a representation of an internal clock converted to something us dumb humans can relate to. Is this guy an idiot or what? If he'd been around many years ago, there wouldn't be binary systems, we'd all have to be on decimal systems, becuase he probably couldn't count either (That'll be his next recommendation.) And what happens when they try and add the 'leap hour'? I'm sure he looks at it like the deficit... he won't be around when it has to be taken into consideration. But I guarantee it'd make the millenium 'bug' (ie, original laziness) look like a cakewalk.
As for 'nobody uses a sextant' since we have good old GPS, tell that to the sailors not too many years ago who lost all nav equip and used hmm... a sextant. One NEVER abandons the ability to utilize alternate means of problem resolution. He figures there's no possibility GPS could ever fail or be subverted? Bad mistake. That's what kills people, not leap seconds. He'd probably be the one to say take INS out of planes since GPS works. Right. I'll never fly over the ocean if he's that ignorant.

Re:now correct me if im wrong

Tweaking by a leap second now and then is far less disruptive than tweaking by an hour every 500-600 years.

Why? If we switch to leap hours, the only software (and that's what the change is about) that will be disrupted by the change will be software that has to be working 500-600 years from now. A lot of programs could safely ignore leap hours, unlike now, when many programs can't ignore leap seconds.

If there were going to be radical changes made to timekeeping, I expect that decimal time would be the top candidate.

Well, this isn't a radical change like decimal time, in that it will have zero effect on John Doe's wrist watch. Second, decimal time is not exclusive with the leap hour; we could do both.

Have they thought about redefining the length of a second (and consequently minute, hour) to achieve these perfect 24-hour days?

Well, we actually can't predict too accurately the rate of the slowing of the Earth's rotation. Leap seconds are added not on a regular schedule, but only when astronomical measurements show they must be.

usual short-sighted thinking by the Americans.

Oh, I get it; you were trolling.

Re:now correct me if im wrong

Have they thought about redefining the length of a second

The second is one of the fundamental units in the metric system. Many other units and constants are based on the second. For example, the speedometer in your car shows miles per hour, the speed of light is given in meters per second, etc. If we changed the value of the second, then either:
a. We'd be forcing the world scientific community to relearn an entire set of new constants, or, more likely,
b. There would be two definitions of the 'second', the US definition and the scientific definition.

I don't think either of these is really what we want.

Re:now correct me if im wrong

The problem is that it isn't working fine. To begin with we should have 13 months in the year, not 12. Months are supposed to reflect lunar cycles and there are 13 of them a year.

Actually, the 12 months was to align with the constellations of the zodiac so that certain constellations will be in the same place at the same time. It keeps astronomical calendars in tune.

Cultures which slavishly kept to a lunar calendar (another method of timekeeping, but it ignores the fact that we revolve around the sun) found that every bunch of years their months would be in the wrong season.

A month is an abstraction made by humans for timekeeping, there is no 'should have 13 months' that closely aligns with actual astronomical time passage, which is far more important.

Keeping track of solstices and equinoxes are really important when it comes to things like knowing when your seasons are changing.

Can we say what we will think 500 years from now?

Sometimes, with our very limited 80 year lifespans, we start to think that everything that we do now is the absolutely most important thing ever, and we make decisions based on that rather than looking to history for a sense of scale. 500 years ago, people weren't reading, they weren't really doing much of anything productive. It wasn't until the Renaissance that things really started humming.

So 500 years from now, with a whole hour of time slip, what will they think of how we just decided to change the manner in which we adjust time?

In China, there is only one timezone, but it works terribly since half the country wakes up in the dark and the other half wakes up in bright sunlight. They have adapted to this by "unofficially" setting work hours according to the longitudinal timezone rather than the government-mandated timezone. I wonder if there were a huge leap second buildup whether people would just start waking up according to the absolute time rather than the political time.

I think it's a bad idea, and I can't think of the benefits. But I guess I'm not a scientist, so I wouldn't understand those issues.

Re:Can we say what we will think 500 years from no

500 years ago, people weren't reading, they weren't really doing much of anything productive.

Except growing food, raising livestock, getting married, raising children, defending themselves, scheming, talking with neighbors, and saying, "Someday Martha, one of our great great great great great ... great grandchildren will grow up to post something stupid on something called the Internet."

I wonder if there were a huge leap second buildup whether people would just start waking up according to the absolute time rather than the political time.

Time is an arbitrary concept created by man. People get up according to when they have to be at work, and if that isn't sometime in the morning they get up when it is convenient for them. Some people have to be at work at 8, others at 9, some at 6 or 7. Where does politics come into this? All the government does is produce a standard benchmark time so we can communicate about time, and know that we will be understood.

Jesus saved me from my past. He can save you as well.

Did he really? Unless this is Jesus the Hispanic fireman, I don't buy it. Either a magic supernatural man in the clouds helped you, or you are confused about it. Occham's Razor anyone?

To illustrate this point, I encourage people to read this: http://www.somethingawful.com/articles.php?a=2800& p=2 [somethingawful.com] (the last post at the bottom). Compare that with what you hear people say about Jesus (the non-fireman one).

Re:Can we say what we will think 500 years from no

Forget time zones - no need for that either

I can see it now... the day will shift mid-day. Try programming that one! The 23rd of August (for example) will change over in the MIDDLE OF A WORKDAY! Not only that, it'll change over at a different time in the work day (so sun's position, but in your proposal not physical time) for every region.

The whole point of time zones is to keep time reasonably standard no matter where you are. I can travel half way across the world and I still wake up at 8am, eat lunch at noon, dinner at 7pm, etc. The concept of a day is very engrained in us. Today is a Saturday! Imagine if it was also sunday based on my location.

Besides- the US would want to manage it, so they'd end up with the same time scheme they have now (probably picking up EST or Mountain as their base zone), while the rest of the world rolls over laughing at their proposal.

-M

Re:Can we say what we will think 500 years from no

First off, you just missed the entire freaking point of the paragraph you cut and pasted. In the absence of Beijing allowing people to live in separate time zones (ala Russia, Canada, US, etc), the people have chosen to implement their own time zones because that's what they want. A global standard for time like this has little purpose when people rarely cross integer numbers of degrees of longitude throughout the course of the day and would rather have a local, sun-based standard that attempts to divide the day into parts based not on where the sun is in the UK, but where the sun is where you're standing right now.

We're diurnal creatures and we liking having a time standard that takes that into account. You can't wish away biology with some global standard.

"My feeling is that they should simply have a chronometer which keeps ISO standard time. "

You misspelled BIPM.

"An office would set their working hours as 1830-0230 and that would be it. No changing the time in the summer/winter/etc. They could change their hours in the summer/winter though."

So, instead of just having to deal with jet lag when I cross multiple degrees of longitude in a short amount of time, I also have to cope with the fact that the operating hours of businesses I've grown accustomed to where I live have absoluntely no meaning here. Instead of today's world where, upon arriving, I simply press a few buttons on my watch, I now have to constantly apply a mathematical operation to what my watch says ("If I'm used to somethign happening at time X at home, then it must happen at X-Y here..."), that all but elminates the purpose of having a timepiece to begin with. I want to know what part of the day it is for the people around me, the people I have to interract with, and if a timepiece can't do that (indeed, begisn to serve as an obstacle to it), it's lost its purpose. I would literally be better off looking at the position of the sun in the sky, thereby eliminating several centuries of progress.

And where you suggest that businesses change their hours instead of simply changing the frame of reference (which is what DST represents), you're advocating a system that would bree chaos. Changing the frame of reference, by definition, is uniform. Every business continues to be adequately synchronized with the other businesses they must deal with in the course of the day. If everybody has to change their own hours, then all you'd do is introduce confusion until everybody agreed on a regular, synchronized change of hours outside of the so-called standard you're proposing (making the standard useless). And even then it would be less efficient than simply changing the clocks.

Have you ever had a physics class? If a problem is set in an ugly change of reference, would you rather constantly have to apply a long list of ugly transforms, or would you rather save yourself a lot of time and effort and simply change the frame of reference?

"An office on the other side of the country might start work at 1700 instead."

Your system also complicates communications across long distances. Time zones simplifies differences in time between two locations into an integer number of hours, allowing a simple calculation to be done after glancing at a clock set in the local frame of reference. Without time zones, everybody would attempt to set their operating times accoridng to time at the local meridian (again, going back to local solar time and making mechanical time standards worthless), and you'd be lucky if the difference between your times and theirs was an integer number of minutes. Intercontinental communications would require a degree of pre-arrangement (to first learn their hours of operation) to make sure that when you attempt to call them, they're there to answer the phone. On the other hand, today I know that businesses across the country (if not across the world) tend to stick with a "nine to five" work day, and all I would need to know is what state or country my

More info

More info here [ucolick.org], with geeky charts and stuff.

over the past 30 years (coincidentally since the inception of leap seconds) the rotation of the earth's crust has accelerated. This acceleration is apparently due to changes of fluid circulation in the outer core of the earth. Historical investigations of earth rotation indicate that such accelerations are not unprecedented, and it should not be possible for the acceleration to continue for very many more years.

Planet

I say we adjust the planet's rotation and orbit so we have perfect intervals.

Re:Planet

I say just blow up the moon, that little bastard is just slowing us down.

Best quote of the article

The astronomers are not convinced. "If your navigation system causes two planes to crash because of a one-second error, you have worse problems than leap seconds," said Steve Allen, a University of California astronomer who maintains a Web site about leap seconds.

That's so right.

Big leap of faith...

Leap seconds and leap days aren't related. Leap days are related to the need to make a year's length expressible in integral number of days by a sort of infinite series approximation. Unless the length of a year were an actual integral number of days, leap days would be needed even if there was no "slowing" ever. By contrast, leap seconds are added to accomodate "slowing" and are not an artifact of the original relation. The use of the term "leap" for both of these is probably what attracts politicians to "leap" to the rescue. Perhaps they should take a second to reconsider...

I actually agree that leap seconds are a bit of a mess, and I wouldn't mind seeing a better solution. But the one proposed sounds a bit bizarre. Surely the real problem is an artifact of the infancy of computer systems and the ad hoc, non-general solutions to time representation we've been using due to very small address spaces that are rapidly falling by the wayside. Why not just delay the issuing of them for a couple of decades until we can think harder about the problem. Pretending that any law passed now is going to stand unused for hundreds of years before it has any effect seems a little ... arrogant. I'm pretty sure that, say, somewhere around 2027, we're going to have a lot of discussion about our present representation of time and whether it's the right one...

The connected geek question

The article talks about lots of problems that leap seconds cause with software.

The problems don't come from the complexity of the underlying problem of adding leap seconds, but rather because leap seconds are added so infrequently that the code to handle the leap seconds isn't well tested.

So the real question here (to me, at least) is this: what do the leap second problems tell us about how software is developed?

Are people not thinking about leap seconds when they write code? Or are they thinking about them, but not testing the leap second cases properly? What's going on?

And how does the emergence of really big collections of APIs affect this? I mean, if people use standard routines for calendar functions, and if people keep their tools up to date, shouldn't these problems be mitigated? Shouldn't we be able to have some hard core calendar geeks solve the problem once in the API, and carry the rest of us?

If that doesn't work, why not?

We can solve this particular problem by changing the calendar. But what if we couldn't, and we had to try to address it with engineering practices? How would we proceed?

Re:The connected geek question

I think it tell us that the people we pay to write critical systems are not doing their job properly. This is going to affect very few systems. Most things will check the system clock, and most properly written systems are set up to automatically check some central time server. There are notable exceptions to this, and those exceptions tend to also be poorly written.

Second, we are talking about a leap second, which happens once every year or so. Not often, but not never. This change is far outweighed by the normal timekeeping error, which for the average watch is like 3 minutes a year. The clock of a computer is not necessarily better. Also, we are only taking about clocks that need to keep track of the time, and not jut the passage of time.

As such we are really talking about a select set of software that much keep up with the time and not depend on a time server. If good techniques are used, the code to handle the leap second is one place, and good regression testing can check many different scenarios to insure that the code will work and changes do not break it. I am not saying it is trivail, but certain not prohibitively difficult. Since we are talking about network critical devices and specific military hardware, I do not see the problem with funding this development. What is really sounds like is that some people took government money for a project, and now want to changes the specs because they cannot do it.

The only other thing i can think of is that these apps are 20 years old and no one want to update them. There is some wisdom to letting working system run, but these are obviously not working. Next legislation will the pi=3, and francium will now be known as freedium.

Astronomers will be unhappy

Doing away with leap seconds has the effect of breaking the connection between the rotation of the Earth and time. The point of a leap second was to compensate for the fact that the Earth changes its rotation rate by very small amounts (due to changes in mass distribution).

It will make it harder to run telescopes, but also a number of navigational devices. The mention of the Glonass screwup is actually misleading - even if you abolish the leap second, you still have to have software in your satellites compensate for changes in Earth rotation rates - abolishing the leap second will not change that at all.

Probably the worst argument for getting rid of leap seconds is "they are rare anomalous events that cause potential danger for systems like ATC that are tightly coupled to time". That's misleading, though, because the proposal is actually to replace leap seconds with leap hours every 500 years. Which means that you replace a small, bi-annual anomaly with a gigantic one 500 years from now (on a scale larger than the Y2K bug, for sure.) Kicking the problem down the road so to speak - I'm not surprised it was originally suggested by a bunch of lazy programmers. Not to mention that that practice would mean that 400 years from now solar noon would be almost an hour away from actual noon (not that big a deal, of course, but annoying).

The argment for keeping the leap second is more than just tradition - it has practical value too.

Egotistical maniac?

Once there was a boy, who longed to be as well known as Julius Caesar. First he gathered his legionnaires and started some wars, but he didn't get the respect from the public he wanted. Then he had a brilliant idea. Julius had a calendar named after him, maybe he could get one too. All he had to do was come up with a plan to show those pesky scientists that time was controlled by God, not some mathematical constant, and if God wanted it to jump ahead by an hour every 5 or 6 hundred years, then dammit, that is what is going to happen. He decided to call his invention the Dubyan calendar, because if he called it Georgian, people might give his daddy credit for it, or even worse, some limey king that died last century.

Re:Hmm...

Powers granted to the Congress of the States:

Section 8, Clause 5: To coin Money, regulate the Value thereof, and of foreign Coin, and fix the Standard of Weights and Measures

Time is a measure, therefore they actually do thave the authority to regulate it.