[ntp:questions] Leap second functional question

David L. Mills mills at udel.edu
Fri Feb 22 19:42:53 UTC 2008


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.


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

More information about the questions mailing list