Re: [LEAPSECS] Mechanism to provide tai-utc.dat locally

From: Rob Seaman <seaman_at_NOAO.EDU>
Date: Thu, 28 Dec 2006 17:00:05 -0700

Poul-Henning Kamp wrote:

> It is not an æsthetic issue, it is an issue of practical
> implementation.

Well, it's both. The big question is practical implementation of what?

> In these days of heavily computerized infrastructure, we need more
> than half a years warning about discontinuities in the timescale.

We've had this discussion before. There are no discontinuities in
the timescale. Leap seconds are a question of data representation.
I'm not trying to minimize the issues by saying that, rather to point
out that we can't solve a problem until we state it correctly.

> We can get that only by increasing the DUT tolerance.

We all understand the trade-offs. Presumably the guys who have
suggested degrading the tolerance to the point that it will outlive
our grandchildren's grandchildren - and simultaneously removed any
requirement for the ITU to distribute DUT corrections - understand
the trade-offs, too.

> I don't care if you want to implement leap-milliseconds, as long
> as you tell me 10 years in advance when they happen.

Again - with no intent to minimize the issues - what supports this
assertion? Is there any reason to believe that 10 years advance
notice would encourage projects and vendors to do anything other than
ignore the requirement entirely? A statement that 10 years, or 600
years, notice is all that is needed to resolve all the problems,
smooth over all the complications, is entirely too glib.

Rather than starting from a bunker mentality of repeatedly fending
off an absurd non-solution, perhaps it would be better to design from
clearly stated use cases, responsive requirements, coherent risk
analyses, a reasonable deployment schedule, a fair-minded budget.
We're not going to successfully define the real world out of existence.

Rob Seaman
NOAO
Received on Thu Dec 28 2006 - 16:00:14 PST