[ntp:questions] A Suggestion For Abolishing the Leap Second

Guy Macon "http://www.guymacon.com/" at ntp.isc.org
Wed Jun 6 10:16:04 UTC 2007

Martin Burnicki wrote:
>Guy Macon <http://www.guymacon.com/> wrote:
>> David L. Mills wrote:
>>>It is important that the leap be substantially complete by the end of
>>>the inserted second, which is done by stopping or almost stopping the
>>>clock for one second.
>> I don't think that the above is correct.  I believe that the clock
>> keeps running and counts off a 61st second.
>I'm pretty sure Dave Mills is correct. For an introduction of leap seconds
>and how they may be handled you migth have a look at
>Search for "normalize" at the end of that section.

I see that. Key phrase:
"2 consequent seconds have the same time stamp"

A post in the comp.protocols.time.ntp mailing list goes into
further detail:

"every time a leap second happens, the fraction part
of the  second, in the NTP timestamp keeps counting. That's 
the fraction part only. It does not roll over to the next 
second. Instead, the same second is repeated - thus we repeat 
the same time, which means we go back in time. However, the 
NTP timestamp sends out a leap second flag, which causes
your computer to go to the 61st second."


It looks like we were both wrong.  The NTP clock doesn't stop, as
David L. Mills wrote, nor does it continue into a 61st second,
which is what I thought it does.  Instead it jumps back a second 
and repeats the 60th second with a leap second flag set.  

Guy Macon

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