[LEAPSECS] Bloomberg announced its smear

Christopher Hoover ch at murgatroid.com
Tue Sep 27 19:11:52 EDT 2016

This I believe is the most recent public statement on the topic:


One could imagine having a public ntp pool on the interwebs that
implemented smearing.  (I know this will be heresy to some.)

73 de AI6KG

On Tue, Sep 27, 2016 at 10:27 AM, Peter Vince <petervince1952 at gmail.com>

> On 27 September 2016 at 14:40, Warner Losh <imp at bsdimp.com> wrote:
> >
> >...
> > Eliminating leap seconds would be a great way to unify all these
> approaches :)
> > And it too is compatible with JTS.
> Smearing seems like a clever way of papering over the problem of the
> leap-second, but as others have said, surely a standard needs to be
> defined, and that way everyone can compare and match their time - surely
> the whole point?
> I am interested that Google have chosen to linearly smear over 20 hours,
> thus increasing each second in that period by 13.8888... microseconds -
> surely such an irrational step is difficult to achieve?  Could it be that
> they actually step 125 microseconds every 9 seconds, or maybe 25
> microseconds every 1.8 seconds?  I wonder if Christopher has any inside
> knowledge on the details?
> I'm also curious about the change from cosine to linear smear: the linear
> smear results in a very sharp step change in frequency, exactly what we
> DON'T do, whereas the cosine smear has a very smooth and gentle change,
> surely more easily followed.  Could it be that this would need some very
> small (way sub 100ns) steps at the start and end which would be almost
> impossible to achieve accurately?  I guess that if we know the time is
> changing at a fixed rate, we can easily allow for that when trying to hold
> a frequency?  Again, does Christopher have any inside info on the thought
> processes?
> However, these new problems, and the Azure systems disagreeing between
> countries, all comes back to what Warner said - scrapping leap seconds
> solves all these problems, at the expense of - with due respect to Rob,
> Steve. etc. - the astronomers having to increase the range of DUT1 on their
> software.
> Peter
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