[LEAPSECS] Leap seconds have a larger context than POSIX

[Tony Finch]

Warner Losh <imp at bsdimp.com> wrote:
>
> Have I forgotten any of the other details of leap seconds that are more
> tribal knowledge than rigorously specified?

The IERS Bulletins C state a value of UTC-TAI "until further notice".

However the machine-readable files from IERS and NIST give an expiry date
of a few days less than 6 months after the announced (lack of) leap
second, or a bit more than 11 months after the latest Bulletin C.
Is this expiry date reliable or just advisory? History suggests it's
reliable, but the standards do not.

It's unclear to me what governs the frequency of announcements or their
validity period, i.e. where are current practices documented? what is the
process for changing them? how will we know if a change is planned? and so
on. This is all about how much we can assume that the IERS will continue
to operate leap seconds as they have for nearly 50 years, or whether they
will make use of the much weaker guarantees given by TF.460, or (wishful
thinking) whether they can schedule leap seconds further in the future.

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/
Cape Wrath to Rattray Head including Orkney: Northwest 3 to 5, occasionally 6
at first near Rattray Head, then backing southwest 4 to 6. Moderate or rough,
becoming slight in Moray Firth. Showers later in north. Good.