In article ,
David Nebenzahl wrote:

On 8/16/2009 10:12 PM isw spake thus:

Functionally impossible. By adding money, you can reduce the drift rate
but you can't make it zero. Period.

I don't care about zero. One minute a month is plenty accurate enough
for me.

Just use NTP. And *stay away* from the stratum one servers like NIST;
they have better things to do than keep your computer's clock on
time.

You're admonishing me not to use NIST? Why?

After all, they offer this service to me. See
http://tf.nist.gov/service/its.htm:

The NIST Internet Time Service (ITS) allows users to synchronize
computer clocks via the Internet. The time information provided by
the service is directly traceable to UTC(NIST). The service responds
to time requests from any Internet client in several formats
including the DAYTIME, TIME, and NTP protocols.

So why shouldn't I use them?

If you need stratum one precision, NIST is not a good choice unless you
live near them; you should choose a stratum one server near to you. If
you don't need that precision but just want your computer's clock to be
decently close all the time, why put an unnecessary load on any of the
stratum one (i.e. high precision) servers? Leave them alone to serve
folks who *do* need that accuracy.

There's a decent number of lower stratum servers that sync to NIST and
some of the other high precision servers. They are specifically intended
to be used by the folks who don't need their computer to be within a
fraction of a microsecond of "actual time".

Lots more info he http://www.pool.ntp.org/

Isaac