nanog mailing list archives
RE: F-ckin Leap Seconds, how do they work?
From: Peter Lothberg <roll () Stupi SE>
Date: Tue, 3 Jul 2012 22:18:24 CEST
The system clock needs to be UTC, not UTC =C2=B1 some offset stuck somewhere that keeps some form of running tally of the current leap second offset since the epoch.Nope. UTC *includes* leap seconds already. It's UT1 that does not.Are you suggesting that NTP timekeeping should be based on UT1?The system clock should be based on UT1 and should be monotonically increas= ing since this matches the common concept of time. Calculations done with = this value are all based on it being UT1 and using the "common" notion of U= T1 rules. The root cause of the difficulties is that someone decided that = the system clock would not maintain "wall clock" time (UT1) but rather some= other timebase and then "step" that time to keep it in sync with UT1. NTP can keep time in UTC (or anything else) if it wants, but it should disc= ipline the system clock to monotonically increasing UT1.
UTC is the universal time. UT1 is "astronomical time". As the definition of a atomic second is 9192631770 complete oscillations of cesium 133 between enery level 3 and 4, "everyone" can make a second in their lab, that's TAI. Just add the lepsecond ofset and you have UTC. UT1-UTC is done by observations from radio astronomers VLBI telecopes and a comitee, you can't make one in your lab, and it's not real time. --P (The only SI metric you can't make is a kilogram, you have to have one of the 28 kilos in the world..)
Current thread:
- Re: F-ckin Leap Seconds, how do they work?, (continued)
- Re: F-ckin Leap Seconds, how do they work? Matthew Palmer (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Bryan Horstmann-Allen (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Steven Bellovin (Jul 02)
- Re: F-ckin Leap Seconds, how do they work? Jimmy Hess (Jul 02)
- Re: F-ckin Leap Seconds, how do they work? Joly MacFie (Jul 02)
- Re: F-ckin Leap Seconds, how do they work? Tony Finch (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Wolfgang S. Rupprecht (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Owen DeLong (Jul 03)
- Re: F-ckin Leap Seconds, how do they work? Jay Ashworth (Jul 03)
- RE: F-ckin Leap Seconds, how do they work? Keith Medcalf (Jul 03)
- RE: F-ckin Leap Seconds, how do they work? Peter Lothberg (Jul 03)
- 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? 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)