[LEAPSECS] leap seconds in POSIX

[Steve Allen]

On Sat 2020-02-01T00:01:22-0800 Hal Murray hath writ:
> I was hoping that there would be a good white paper or blog that discussed all
> the possibilities that have been considered and explained why they were
> rejected.

That cannot happen because of the other factor that has been in the
politics of time since the 1950s: fear

The surviving scientific and technical discussions indicate that two
time scales were considered a plausible option.  It was the regulatory
context of the CCIR where two time scales were deemed unacceptable.
The memoirs of the participants indicate that those discussions
happened at conferences where the principals gathered but which were
not actually part of the bodies who actually exercised authority.
The discussions where the decisions were made are not recorded,
and the discussion of those discussions at IAU 1970 was redacted.

The fear comes from the fact that the broadcasts of time were funded
by national governments.  The urgency to adopt leap seconds came from
the German law that which disenfranchised the German Hydrological
Institute that had been providing old rubber second UTC and declared
that only the PTB with its cesium seconds was able to provide legal
time.  If bureaucrats and lawmakers in other countries had access to
documents which described the dichotomy between SI seconds and
calendar days they might have legislated differently, and that would
destroy decades of efforts to get all radio broadcast time signals to
supply the same time scale.

The fear seen in the redaction of the 1970 IAU proceedings is still
clear early in 1972 just after the inception of leap seconds where
G.M.R.  Winkler of USNO (who was in charge of the 1970 IAU redaction)
explicitly cautioned against open discussion of legal issues.  By 1974
there had been enough recommendations and acceptance of UTC with leaps
that Winkler openly remarked "The C.C.I.R.  may have overstepped its
remit in defining UTC" and then paraphrased Spock "The process that
led to UTC may have been illogical, but it was effective."

The problem for POSIX and any technical implementations follows from
the carefully worded recommendations that were handed to bureaucrats
to get their approval.  The wording allowed the insiders to implement
what they understood to be the only politically acceptable compromise.
Anyone outside the process was thereafter condemned to conform to
specifications for a political compromise that gave no clues about its
underlying technical barrenness.

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