[tz] Bulletin C 51: No leap second in June 2016, but new leap second file

Brian Inglis Brian.Inglis at systematicsw.ab.ca
Wed Jan 13 00:33:35 UTC 2016

On 2016-01-12 15:09, Paul Eggert wrote:
> In http://mm.icann.org/pipermail/tz/2016-January/023057.html Brian Inglis wrote:

> A less-important issue: that web page has a Last-Modified time
> (reported via the HTTP header) of 2016-01-11 11:06:36 UTC, even
> though the web page's contents give a last update equal to 3661459200
> NTP, i.e., 2016-01-11 00:00:00 UTC. I guess they have just one-day
> resolution for theirannouncements' time stamps, but hey! they're time
> nerds! The two time stamps should be identical.

They're time nerds, not necessarily IT nerds who know how to propagate
time stamps thru whatever process results in the publication of the file
on the public facing web site. Whether that process involves Unix cp,
scp, or internal FTP put, these operations do not normally propagate
file timestamps.

>> so they must be fairly confident
>> that current predictions of dUT1 remaining low until year end will be
>> borne out, and Bulletin C 52 will announce no change in July.
> If the actual expiry is 2016-09-30 they're giving themselves the
> opportunity to decide in July to insert a leap second at the end of
> September, which is conservative: although the protocols allow leap
> seconds to be inserted in September, it has never happened and is
> unlikely to happen this year.

I read that as giving themselves just 12 weeks leeway rather than the
normal 24 weeks over the normal July update timeframe in case some
event(s) are expected to increase dUT1 divergence more than the -0.4s
currently predicted for year end in Bulletin A.

Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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