Re: [LEAPSECS] ITU Meeting last year

From: Poul-Henning Kamp <phk_at_phk.freebsd.dk>
Date: Thu, 20 Jan 2005 21:17:45 +0100

In message <20050120192429.GD5069_at_ucolick.org>, Steve Allen writes:

>In the hopes of enlightenment for this list, but without the ability
>to authenticate these draft documents, I offer the following:
>
>http://www.ucolick.org/~sla/leapsecs/SRG7Afinalreport.doc
>http://www.ucolick.org/~sla/leapsecs/PropRevITU-RTF460-6.doc

Looks good to me.

>It seems that atomic clock keepers have lost all interest in the
>continued existence of mean solar time, sundials, or the analemma.

And why shouldn't they ? The job of atomic clock keepers is to
keep TAI ticking.

I really can't see any problem with the proposal above which even
get into the same order of magnitude to the problems and inconvenience
leapseconds are today. And I applaud them for setting a transition
date which I think would spare us for even one more leap-second.

As a private person living at 1120'22.98" the sun is never in south
at noon anyway and we have voluntarily moved it a further 15 away
from south half the year already with daylights savings time. I
already need to adjust my sundial twice a year anyway (OK, so I'm
also at 55N24' so it's not much use during winter so I don't
actually bother but that's besides the point :-).

As a computer nerd I can fully appreciate the problems and cost of
converting existing systems to cope with larger UT1/UTC difference,
but that cost would be peanuts compared to the costs of implementing
leap-seconds reliably in future systems that would need it.

And for that conversion cost: Just how hard is it to make a computer
synchronize with NTP over the internet, pick the DUT1 up from IERS
homepage and emit clocksignals which are UT1 approximations for those
old computers anyway ?

I know several operations computers here in Denmark which think it
is 1985 because they cannot cope properly with years in a different
century, people can live with that kind of quirk in old computers.

Finally as goes with navigation, here in Denmark celestial navigation
is now taught as a "historical interest" course...

So yes, we might loose a ship or two if they for some reason rely on
celestial navigation. Chances are very good that they were in dire
straits already, otherwise they wouldn't have taken their eye off
the GPS receiver and the radar long enough to locate the sekstant.

Compare that to the number of deaths of just one major software bug
triggered by a leapsecond, and things come into perspective nicely.

--
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.
Received on Thu Jan 20 2005 - 12:28:33 PST

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