Re: [LEAPSECS] interoperability

From: Tom Van Baak <tvb_at_leapsecond.com>
Date: Sun, 8 Jan 2006 15:04:56 -0800

> Without further debating the meaning of "civil time", consider the
> implications of this two stage system. The first stage conveys TAI
> or something related to it by a constant offset. The second stage at
> any location (correct me if I misunderstand you) would be a secondary
> clock disseminated at the direction of the local authorities.
> Governments and technical users would subscribe to the first stage
> clock. Businesses and civilians would subscribe to the second stage
> clock(s). Correct so far?

I think this was a fair description of the timekeeping
world in the 1960s or even 1970s.

But in the last 10 or 20 years, with the explosion in
consumers of broadcast time and frequency services
such as WWVB, DCF, GPS, and NTP, vast numbers
of applications have direct access to the "first stage";
which effectively removes the power of the middle man,
the government, the "local authorities".

What was your human "technical user" of 1970 is now
the infrastructure of the cellular phone system or the
hardcoded algorithms of an operating system or home
appliance. The technical users of the 60s have coded
themselves into products of the 90s.

You cannot divide timekeeping, time dissemination,
into neat stages. In the 1960s if ten labs were told
to offset their phase or frequency it affected only a
handful of people or systems. Today when IERS
announces a leap second, millions of machines,
systems, and people are affected. Thankfully, most
of them handle it OK.

/tvb
Received on Sun Jan 08 2006 - 15:07:00 PST