Re: Leap second functional question

Danny,

A little history here. A few years ago industry lobbyists persuaded the State Depatment to propose abolishing leap seconds to the ITU-T (nee CCITT) without a public discussion first. The astronomers and timekeepers around the world are still seething about what they perceive as American arrogance.

More history. NTP and competitors have been very much in the crosshairs of the ISO and ANSI in various study groups. A few years ago the targets were Probabilistic Clock Synchronization (PCS), DECnet Time Service (DTS) and NTP. In typical standards culture a provisional application interface (similar to DTS) was proposed, but not the guts of the timekeeping vehicle itself. So far as I know, the project is DoA.

Whether NTP runs on UTC, TAI or moonbeams is actually moot. It runs on whatever the radios say. If the radios deliver UTC, NTP runs on that and delivers the TAI Offset as available. If the radios deliver TAI, NTP runs on that and could in principle deliver the UTC offset. The latter is the IBM mainframe model, but even they have to use UTC as deliverd by the radios and manually introduce (!) TAI, leap second and timezone offsets.

Dave

Danny Mayer wrote:

Unruh wrote:

Having ntp run on TAI would certainly be simpler, but would of course make
the time keeping on the system much more complicated.

That question has already been discussed at length in this newsgroup.

And will keep getting discussed since there is no resolution which is
uniformly positive.


Actually no. We don't get a vote on this. This is being voted on by the ITU (or whatever the replacement is for the CCITT) if I recall correctly. It's a separate question whether or not NTP will continue with UTC if they do something stupid with the decision.

Danny
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Relevant Pages

  • Re: [ntpwg] Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009
    ... need for NTP to provide TAI information since NTP only uses UTC. ... Operating Systems use UTC and not TAI by universal agreement and the ... the Linux kernel keeps time in UTC. ...
    (Linux-Kernel)
  • Re: Leap second functional question
    ... I know we are really dating ourselves by referring to the CCITT! ... NTP and competitors have been very much in the crosshairs ... Whether NTP runs on UTC, TAI or moonbeams is actually moot. ... whatever the radios say. ...
    (comp.protocols.time.ntp)
  • Re: [ntpwg] Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009
    ... need for NTP to provide TAI information since NTP only uses UTC. ... If you don't have NTP running for some reason when a leap second is ... Operating Systems use UTC and not TAI by universal agreement and the ...
    (Linux-Kernel)
  • Re: Lep seconds
    ... if a client syncrhonizes to a server strictly running TAI ... and never signals leaps, NTP will deliver TAI. ... to continue with NTP on UTC. ... Both POSIX and NTP use UTC. ...
    (comp.protocols.time.ntp)
  • Re: Lep seconds
    ... Conversely, if a client syncrhonizes to a server strictly running TAI and never signals leaps, NTP will deliver TAI. ... USNO and I have discussed this serveral times and concluded the lessor of two evils is to continue with NTP on UTC. ... Actually, POSIX does *not* use UTC in the normal sense of the word, as no leap seconds are applied. ...
    (comp.protocols.time.ntp)