[tz] What's "right"?

[John Sauter]

On Mon, 2020-11-16 at 10:29 +0000, Michael H Deckers wrote:
> 
> On 2020-11-15 23:21, John Sauter wrote:
> > If I am reading section 9.4 correctly, they are defining two time
> > scales: the old scale (before the leap second) and the scale after
> > the
> > step.  In the old scale the leap second at the end of 2016 would
> > start
> > at 2016-12-31T24:00:00 and end at 2016-12-31:24:00:01.  In the
> > scale
> > after the step the leap second would start at 2017-01-01:00:00:-1
> > and
> > end at 2017-01-01T00:00:00.
> 
> 
>      Yes.
> 
>      The rationale of a positive leap second notation for a time
> point
>      is to indicate that the point does not belong to the normal
> range
>      of datetime values, where there are only 20 seconds from
>      2016-12-31T23:59:50 to 2017-01-01T00:00:10. One therefore has
>      to use a notation that cannot be confused with notations that
>      are used for these normal datetime values.
> 
>      Exceeding the normal range [0..1[ d of time of day is one
>      method; the ITU method uses times of day >= 1 day, but times
>      of day < 0 d could similarly be used. Other means would be
>      affixes to the notation (such as the leap second bit in the
>      Ada programming language, or the labels "A", "B" proposed to
>      distinguish duplicate timestamps during fall back from summer
>      time in Denmark and Germany).
> 
>      Michael Deckers.

In addition, following Steve Allen's suggestion, the start of the leap
second in the time scale after the step could be 2017-01-00T23:59:59.
    John Sauter (John_Sauter at systemeyescomputerstore.com)

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