Re: [LEAPSECS] A lurker surfaces

From: Steve Allen <sla_at_UCOLICK.ORG>
Date: Sun, 31 Dec 2006 05:12:48 -0800

On Sun 2006-12-31T07:59:35 +0000, Poul-Henning Kamp hath writ:
> Rob, If you feel uncomfortable with calling leapseconds
> discontinuities, then we can use the term arrhythmia instead.

The point of my allegory about unplanned pregnancies is that
all practically available time scales have arrhythmias.
Almost everything has jumps at some point during power on self test,
and the national time bureaus (and the GPS almanac) publish their
current estimate of their deviation from regularity. If you can
handle leap seconds, then you can handle reality. The decision made
37 years ago was that the reality of most systems didn't/couldn't care
about seconds, and that's the part that now is getting scrutiny.

What tweaks me is that I get the impression that a lot of folks are
perfectly willing to accept those irregularities and to let Dave Mills
diddle with the rates of their system clocks so long as they never
have to admit the existence of a named leap second. It's as if
everything is okay so long as the baby never comes to term -- everyone
can live in denial about those things going on behind the scenes --
but as soon as the county recorder gets that birth certificate with
Mr. Astronomer named as father the social order of the world breaks

I see this as a form of denial. Almost all applications may be
capable of tolerating the level of irregularity in the currently
practically available time scales, but they are irregular.

What happens in a world with terabit per second information streams
coming over fibers from sources whose clocks, even if they are
ion-trap clocks (especially if so), are different tidal potentials
that vary diurnally? (Of course the glib answer is that if the
optical fiber engineers do manage to notice this first then they will
win the Nobel prize just as surely as Penzias and Wilson did after
they found that cleaning pigeon shit out of their microwave horns did
not manage to make the background noise go away.)

What happens in a world where systems begin to be sensitive to the
effective leap microseconds or variations in length of seconds which
happen even if Dave Mills is conditioning their clocks?

It's my expectation that if all systems are allowed to deny the
reality of precision time keeping we will eventually find ourselves
living in a timekeeping world that resembles C.M. Kornbluth's story
The Marching Morons.

Steve Allen                 <>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99858
University of California    Voice: +1 831 459 3046           Lng -122.06014
Santa Cruz, CA 95064     Hgt +250 m
Received on Sun Dec 31 2006 - 05:13:16 PST

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