[ntp:questions] Leap second functional question

Richard B. Gilbert rgilbert88 at comcast.net
Tue Feb 19 17:00:14 UTC 2008


Unruh wrote:
> Paul.Croome at softwareag.com writes:
> 
> 
>>On Feb 18, 3:41 pm, Unruh <unruh-s... at physics.ubc.ca> wrote:
> 
> 
>>>NTP time is UTC which assumes 86400 seconds in each and every [[year]] day.
>>
>>...
> 
> 
>>My understanding is the opposite: In the UTC time scale, the
>>minute, hour, day, week are of variable duration, depending
>>on the insertion or deletion of leap seconds.
> 
> 
>>In the TAI time scale, the minute, hour, day, week are of
>>constant duration.
> 
> 
> No, in UTC all years are 86400 seconds, even if during that year a second
> was added or subtracted. Ie, utc retains no memory of leap seconds. Thus a
> year with a leap second added has 86400 UTC seconds but 86401 TAI seconds.
> UTC simply erases that leap second from memory. It never existed.
> 
> 
> 
>>Paul
> 
> 

The most interesting thing about leap seconds, as far as I'm concerned, 
is the fact that the last leap second left the timing world in disarray 
for about twenty-four hours.  Some added a second, a few subtracted a 
second and some ignored the leap second.  It took a long time and, I 
suspect, considerable manual intervention to get all the clocks synched 
up again!





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