nanog mailing list archives
Re: F-ckin Leap Seconds, how do they work?
From: Jay Ashworth <jra () baylink com>
Date: Tue, 3 Jul 2012 16:26:57 -0400 (EDT)
----- Original Message -----
From: "Keith Medcalf" <kmedcalf () dessus com>
Are you suggesting that NTP timekeeping should be based on UT1?The system clock should be based on UT1 and should be monotonically increasing 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 UT1 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.
UTC is monotonic, and is based on UT1. Just not deterministically. :-) The root cause *is* that someone made a bad decision about kernel timekeeping, but it wasn't the choice of timescale. Non-monotonic time is not a feature of UTC *either*.
NTP can keep time in UTC (or anything else) if it wants, but it should discipline the system clock to monotonically increasing UT1.
As I undertstand it, the problem is not how NTP disciplined the kernel, it's what the kernel does itself. Cheers, -- jra -- Jay R. Ashworth Baylink jra () baylink com Designer The Things I Think RFC 2100 Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274
Current thread:
- RE: F-ckin Leap Seconds, how do they work?, (continued)
- 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)
- 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)