[LEAPSECS] Windows Server 2019

Steve Allen sla at ucolick.org
Mon Jul 23 11:40:16 EDT 2018

On Fri 2018-07-20T12:16:07-0600 Warner Losh hath writ:
> Unless you are at UTC+0, I don't see how this can be right... Leap seconds
> happen during the day for most time zones...

On Fri 2018-07-20T16:11:12-0400 Stephen Scott hath writ:
> What I am asking is WHY.
> Where is the standard for that?
> Or at least some document that specifies that?

On Mon 2018-07-23T14:05:13+0100 Tony Finch hath writ:
> The standard for leap seconds is ITU-R TF.460
> https://www.itu.int/rec/R-REC-TF.460/en

Most legislation and decrees about legal time specifies that the local
civil time is some number of hours and minutes different from GMT or
UTC.  Taking the simplest interpretation on January 1
on every other day      23:59:59 UTC is 15:59:59 PST
on every other day      00:00:00 UTC is 16:00:00 PST
so most simply          23:59:60 UTC is 15:59:60 PST
If the base time in the law or decree is GMT (as it was in the US
until 2007) then all of this is by convention following whatever
official metrology agency is tasked with providing legal time for that

A law could specify what Microsoft reportedly did in Azure, that is,
Kiribati could apply the leap at the begin of their January 1 13 hours
before of 0h UTC, and Hawaii could apply the leap 11 hours after 0h
UTC, but it is hard to imagine legislators and bureaucrats getting
that specific unless their metrology agencies provided powerful
technical arguments about why being off by one second for all of those
hours was less harmful than taking the leap second in the middle of
the day.  That might happen if some international regulatory or
scientific agency produced a recommendation saying that every nation
should do leap seconds at local midnight, but that just moves the
"hard to imagine" into a different arena.

Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
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