[LEAPSECS] content of the NTP-aimed leap-seconds.list files

[Rob Seaman]

Zefram <zefram at fysh.org> wrote:

> My Charlottesville paper
> <https://www.fysh.org/~zefram/time/prog_on_time_scales.pdf> gives a
> list of desiderata that includes the above, and some others, but without
> much rationale.
> 
> I've been wondering whether the file format should be textual or
> binary.  Possibly both should be specified: the binary format for easier
> machine-readability and for smaller space usage, and the textual format
> for human readability and editability.  It would be trivially possible to
> convert between the two formats.  Also, I wonder about the check field
> in a textual format: it should probably be optional, to support human
> editability, though highly encouraged for published files.
> 
> I imagine the body of the textual format looking something like this:
> 
>    1972-01-01 1972-06-30 +10
>    1972-07-01 1972-12-31 +11
>    1973-01-01 1973-12-31 +12
>    ...
>    2009-01-01 2012-06-30 +34
>    2012-07-01 2015-06-30 +35
>    2015-07-01 2015-12-31 +36
> 
> That is, tuples of start date, end date, TAI-UTC difference.  Leap events
> are implied by different TAI-UTC differences on consecutive days.
> End date of 2015-12-31 above doesn't imply that there'll be a leap
> on that day, just that it's the end of the period for which we know
> TAI-UTC = 36 s.  Dates given in Gregorian calendar and ISO 8601 for human
> readability (unlike leap-seconds.list, which despite being textual is
> effectively impossible for an unaided human to understand).
> 
> Anyone interested in me working up a full spec?
> 
> -zefram

If you were to lead the writing of it one imagines many would like to read it :-)  Surely everybody here regards you as an impartial arbiter.  There are numerous external stake-holders, of course, and the WRC and tzdist deadlines may not be the only pertinent calendars.

Rob