From: Peter Vince <pvince_at_THEIET.ORG>
Subject: Re: [LEAPSECS] Equitable estoppel
Date: Mon, 18 Dec 2006 20:15:50 +0000
Message-ID: <v04210100c1aca65ca59b_at_[10.0.0.3]>
> >For the moment, if leap seconds is to be abbandoned, I would favour the leap
> >minute instead.
>
> Is that not sitting on the fence, and ending up with the worst of
> both worlds? It is neither as precise as leap (micro, milli, or
> whole) seconds, nor as long term as leap hours. It would put off the
> updates for only a few tens of years, by which time experience of
> them would have been lost, and our descendants would end up with Y2K
> type problems.
Well, to start off with, I beleive that a leap <anything> mechanism is needed.
Let's now assume that everyone agrees on that (I know that some people want to
abandon them altogether).
What type of leap mechanism do we want? The leap micro, mili stuff we have
already tried, and it was abandoned. This is why leap seconds was introduced.
Infact, the original 0.7 second deviation was relaxed to 0.9 seconds after a
few years. There is some arguing that leap seconds is hard since they can't be
predicted long enought in advance. Frequency offsets and smaller jumps don't
work so if a leap mechanism is needed it needs to be for large jumps. Being the
sillly humans we are, the units we have left is minute, hour and day.
Since I beleive that there is a practical usefullness of keeping a rougth
coordination between UT1 and UTC such that UTC/legal time is still relevant for
identifying morning, noon and stuff, the day (and larger jumps) is ruled out.
That leaves minute and hour. Both these we should be able to plan well in
advance considering the rates we have seen so far. The benefit about doing it
in minute is that the leap minute would at least occur so often that people
actually recalls that they can occur and design for it, plan it and roll it out
where as leap hours would occur so rarely (at least in nearby time) that you
will have Y2K all over again. Not that any of us would be around by then, but
sure as hell they would say how stupid we where. Ah well.
This is why I say that if we are to abandon leap seconds, my preference would
be leap minute. Abandon the UT1 - UTC regulation alltogether is not a good
solution IMHO even if I respect the views that leap seconds is troublesome in
systems, and then mainly (as I have gathered) due to their fairly high rate
and unpredictabilty.
The noise prohibit us from mechanics such as the leap day rules, which would
have to be adjusted down the line. So, we seem to require administered leap
mechanisms as I see it.
Cheers,
Magnus
Received on Mon Dec 18 2006 - 16:33:57 PST