[time-nuts] Win XP and NIST time

Anthony G. Atkielski anthony at atkielski.com
Tue Mar 26 01:56:38 EDT 2013


Chris writes:

> For most users I think that is reasonable.   It's just not what one
> expects to read on  a "Time Nuts" list.  Here we expect to see posting
> from true nut-cases who want microsecond just because they can do it.

But how can you verify microsecond accuracy on Windows? Even the OS
only has 10 ms resolution for the system clock.

I think there are different ways to be nuts about time. I like time
measurement that is extremely accurate over long periods. Like my
Waveceptor watch, which is accurate to within 1 second in 30 million
years over the long term (because it syncs with atomic time), although
it's free-running accuracy is only about a few hundred milliseconds
per day, and its probably off by a few tens of milliseconds regularly,
due to propagation delay and such.

For me, it's okay if the clock is 10 microseconds off, but it's not
okay if it's off by 10 microseconds today, 20 usec tomorrow, 40 usec
the day after, and so on.

I guess it's the difference between time-of-day measurement and
interval measurement. I'm particularly fascinated by time-of-day
measurement, but much less so by interval measurement. Perhaps because
TOD is easier to verify directly through human perception, whereas
with interval measurement you quickly become dependent on machines for
verification.

--
Anthony



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