In article ,
Jeff Liebermann wrote:

On Mon, 17 Aug 2009 07:41:19 +0100, "Dave Plowman (News)"
wrote:

In article ,
David Nebenzahl wrote:
I agree that for most a minute per month is reasonable but I would
expect the same accuracy as my $29.99 Timex wris****ch which is more
like a second a month.

So that kinda begs the question of why computer mfrs. can't (or won't)
include clocks that are at *least* as accurate as a Timex, no? Wouldn't
a computah be a more compelling reason for a more accurate clock? (I
know, $$$ bottom line, right?)

Wonder if it's because a wrist watch is kept at a pretty constant
temperature via the skin?

Do you really expect people to wear a watch when they sleep just to
maintain accuracy? There's quite a difference in temperature between
skin temp (about 37C) and room temperature (about 25C). The same for
a computah. When turned off or in standby, the clock is slightly
above room temperature. When running, it might be as warm as 75C.

Yup, but the long-term average will be pretty good -- gain a little in
the daytime, lose a bit at night (or the other way around; could be
either one depending on how the circuit was set up).

Remember the old "Accutron" watches -- the ones with a tuning fork
inside? You could adjust those by deciding which way to lay them on the
table when you went to bed. "12 up" would run at a different rate than
"12 down" because of the effects o gravity on the fork. Also, they ran
noticeably fast on airplane trips, due to thinner air.

Isaac