[ntp:questions] Lep seconds

David L. Mills mills at udel.edu
Fri Jan 4 15:09:46 UTC 2008


Conversely, if a client syncrhonizes to a server strictly running TAI 
and never signals leaps, NTP will deliver TAI. NIST, USNO and I have 
discussed this serveral times and concluded the lessor of two evils is 
to continue with NTP on UTC.


Joseph Gwinn wrote:

> In article <T1199401837 at ex.djwhome.demon.co.uk.invalid>,
>  david at ex.djwhome.demon.co.uk.invalid (David Woolley) wrote:
>>In article <298286.52982.qm at web55415.mail.re4.yahoo.com>,
>>marknmbox-88 at yahoo.com wrote:
>>>compliant.  Is there a similar mod for NTP.  I am
>>>hoping that there is a mod that will cause NTP to
>>>supply theoretical UTC (even if it is not ascci).
>>Both POSIX and NTP use UTC.  Your problem is that you are not using
>>using UTC, but, rather, using TAI.
> Actually, POSIX does *not* use UTC in the normal sense of the word, as 
> no leap seconds are applied.
> The fundamental POSIX timescale counts what amount to SI seconds from 
> the POSIX Epoch, 0h 0m 0s UTC 1 January 1970.  Every day contains 
> exactly 86,400 seconds.
> That said, if one drives a POSIX box via NTP from a GPS timeserver set 
> to emit UTC (versus GPS System Time), time on the POSIX box will be 
> pretty close to UTC.
> Joe Gwinn

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