[ntp:questions] Re: Leap second talks are postponed

David J Taylor david-taylor at blueyonder.co.not-this-bit.nor-this-part.uk.invalid
Mon Nov 21 16:20:02 UTC 2005

David L. Mills wrote:
>> Windows W32time appears to handle leap seconds better than NTP on
>> Windows right now, according to earlier discussions - it avoids the
>> step change. David
> David,
> You are gloriously misinformed. The NTP daemon does not do leap
> seconds; the kernel does. NTP is not good or bad, just the messenger.
> However, the model now used in FreeBSD, Solaris, Linux and Tru64 is
> derived from my code as described on the NTP project page. You get to
> smear me in the media based on that model, not NTP. There is no step
> change in that model, just stopping the clock for the leap second,
> but allowing forward progress to conform to the correctness
> assertions.
> Dave

Well, of course, it's implementation dependant, so my comment was 
addressed to the implementation part, not to NTP itself.  Good to hear 
that some OS kernels have adopted your ideas.

If I'm wrong, please correct me but, as I understand it:

- NTP will step the clock on Windows at the leap second or sometime 
shortly after.

- W32time will slew the clock at double its normal rate soon after the 
leap second.  This behaviour has only recently been reported.

To me, the slew seems better than the step.  I believe that the Windows 
implementors are looking at updating the code.


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