nanog mailing list archives
Re: F-ckin Leap Seconds, how do they work?
From: George Herbert <george.herbert () gmail com>
Date: Tue, 3 Jul 2012 20:15:42 -0700
On Tue, Jul 3, 2012 at 4:48 PM, Owen DeLong <owen () delong com> wrote:
.... Most people operate on the assumption that there are 86400*365.25 seconds per year overall and that every day is 86,400 seconds. UTC matches that common conception of time. UT1 does not because UT1 monotonically increments one second for every elapsed second of time and continues to drift out of synchronization with the celestial phenomena on which the common conception of time is based.
Let's be clear - the "celestial phenomena" vary regularly. The Sun and Moon do not rise and set at the same exact time every day; people would not practically notice a second-a-year skew in this for decades or longer, much less societally have grounds to object to it. And it's only historically been about 0.625 s / yr averaged since 1972. At that long term rate (if that's what it ended up being) it would be about a minute a century, or 6000 years before we saw things happening a whole hour off from "expected solar time", which to be frank stops being meaningful around when you have real clocks and astronomy. The only people for which the celestial phenomena timing matters this precisely are astronomers, who ALREADY have to do their own things to keep everything straight, much more precisely than the leap seconds correct the ongoing skews. This (irregular leap seconds) is a solution which is monumentally badly matched to the actual problem set.
NTP can keep time in UTC (or anything else) if it wants, but it should discipline the system clock to monotonically increasing UT1.This will break many many currently correct applications and is not a change that should be undertaken lightly. Especially not if it is intended to fix a moderately esoteric bug in a few things that crops up once per decade or so.
I would argue exactly the opposite. It's unpredictable and irregular enough that a nearly completely new set of software and administrators are what encounters it each time it comes through. It broke chunks of the internet this time. Last time, this was a "Oh, well, some geeks inconvenienced, shrug". This time it was fortunately small enough (esp. in comparison to the recent AWS outage due to more malign natural forces) that it wasn't a big deal. It could be more disruptive next time.
From an Internet Stability point of view, one can easily take the
position that This Just Does Not Do. So - It's there to keep us in sync with the stars, except it's done in increments nobody will notice but astronomers, who have to do better than that anyways; it disrupts technology, to a mild to moderate degree. Why are we doing it again? I like this atomic time thing. It's sounding better and better each day we keep arguing about it. If it bothers you that much we can schedule in a leap hour for Y8000 (or, Y5000, Y11000, Y17000, ....). It's not a butthead thing to do to assert that the Internet's stability in this matter now outweighs an arbitrary and abstract argument among timekeepers. We matter more than they do, now. If they want to keep a more true Solar Time they can do so; we can run on atomic and put this silly notion of trying to say Sun-centric behind us. This is the 21st century. Leapsecondo Delenda Est! -- -george william herbert george.herbert () gmail com
Current thread:
- Re: F-ckin Leap Seconds, how do they work?, (continued)
- Re: F-ckin Leap Seconds, how do they work? Tony Finch (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Vadim Antonov (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Steve Allen (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Vadim Antonov (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Christopher Morrow (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Jimmy Hess (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Peter Lothberg (Jul 05)
- Re: F-ckin Leap Seconds, how do they work? Jay Ashworth (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Owen DeLong (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Steve Allen (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? George Herbert (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Tyler Haske (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Majdi S. Abbas (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Tyler Haske (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Robert E. Seastrom (Jul 04)
- Re: F-ckin Leap Seconds, how do they work? Jimmy Hess (Jul 04)
- Re: F-ckin Leap Seconds, how do they work? Steve Allen (Jul 04)
- Re: F-ckin Leap Seconds, how do they work? Scott Howard (Jul 04)
- Re: F-ckin Leap Seconds, how do they work? Dave Hart (Jul 05)
- Re: F-ckin Leap Seconds, how do they work? Peter Lothberg (Jul 05)
- Re: F-ckin Leap Seconds, how do they work? Saku Ytti (Jul 03)