[LEAPSECS] Regarding the ITU's very immodest proposal

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Feb 12 15:13:47 EST 2008

In message <0802121924.AA22829 at ivan.Harhan.ORG>, Michael Sokolov writes:

>Rob Seaman <seaman at noao.edu> wrote:

>I think I know who they are. They are the PHKs of this world.

I am honoured to be made the clavis of an entire population segment,
but I think you have confused my *interpretation* of the situation
with my *opinion* about the situation and therefore ascribe me a
single-mindedness about the issue, which I don't posses.

It's a common mistake, not being able to tell opinion from
interpretation, because most people don't have more than the same,
those of us are capable of seeing things from more than two sides
at once get used to it after some time.

So let me make my *opinion* clear:

I have only one thing against leap-seconds: they don't work in
practice because the six month warning is an order of magnitude
to short.

I'm totally agnostic on the question of solar time or for that
matter, the duration of the second, and all that. (As a time-nut
I love to play with it, but that's a different story).

All I want for the worlds computerbased infrastructure, is a time
definition that has at least 20 times longer than a six month horizon
of predictability.

Therefore my first proposal was:

Change the rules as follows:

"Leap seconds must be announced 10 years in advance".

10 years warning is fine for the computer business, we'll get around
to update the table before then, it can be done during regular
software maintenance, instead of as a mad scramble where nobody
know anything or have time to test anything properly.

There is still a lot of expenses for coding, testing and fall out
from bugs in the code, and that must be counted on the balance
sheet against the value of leap second adjustment.

The obvious fall-out is that the +/- 1s DUT1 cannot be guaranteed,
unless BIPM's models are good enough, and they'd better be because
the tolerance band needs to go from the text: we can't have two
conflicting rules.

But exactly because I'm totally agnostic on solar time, the obvious
follow up question is: why leap seconds at all ?

People live up to 5 hours away from solar time already today, so
it cannot be very important to have the sun in south at noon.

So we can save the expense of handling leap-seconds in software
entirely by dropping leapseconds.

We would have to maintain earth rotatation angle as a scientic
exercise, along with all the other earth rotation parameters.

This already happens with greater precision than UTC ever had.

If informing the world, as such, that the civil time makes a jump
in six months time can be done by email, it is unlikely that the
dissemination of the earth rotation angle is going to be a technical
challenge for the highly intelligent usercommunity of that measurement.

We can leave any necessary adjustments to civil time, if/when night
turns into day, to the national governments who already are far too
keen to fiddle timezones for their own economic welfare.

Downside ? People with thing pointing to extraterrestial objects
are going to be cross, but they'll get over it.

And that is, pretty close, the proposal in WP7A, except they mention
the "leap-hours" as a silly figleaf to the astronomers and other
die-hard sun-in-the-south-at-noon (mostly religious) addicts.

There, now you know my *opinon*, then let me give you the
*interpretation* also:

USA launched the proposal in WP7A.

We have, as far as I know, never identified which agency, branch
or entity in USA was the instigator, but there is plenty of reason
to suspect the strategic forces and their expensive standdown routine
whenever too many digits on the clock changes at the same time.

Although, I wouldn't be surprised if people in Air Traffic Control
and to some extent telecoms have nodded violently in agreement.

Nothing of any technical nature has any influence on the proposals
chances of getting ratified in ITU, that's purely a matter of
politics, most of it under the radar at civil servant level, and
once the plenum vote approaches, also at ambasador level if USA
feels badly enough for this.

All the moral high ground studies, propoals, round-tables
Rob is looking for, are not going to happen if the people behind
the proposal can avoid it: We know their aim is to kill leap-seconds
as fast as possible (from the fact that the original proposal tried
to preempt the next likely leap-second).

Therefore, if Rob wants to keep leap seconds, he knows where to go:
Find the people in USA who are pushing, and offer them a better
suggestion, that works both for him, and them.

If, as you claim, I am the clavis for this group, then Rob can use
my *opinion* above to guide that effort, but don't take it for dicta.

And should we stop the name-calling while we're at it ?


Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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