[ntp:questions] Leap second functional question

Danny Mayer mayer at ntp.isc.org
Fri Feb 22 22:38:29 UTC 2008


I know we are really dating ourselves by referring to the CCITT! In any 
case when the people making these recommendations recognize the having 
midnight and midday exchanging places so the new days starts at noon (ie 
when the sun is highest in the sky) hopefully they will desist from this 

David L. Mills wrote:
> 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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