In article , root
wrote:

isw wrote:

What the NTP process does is essentially to monitor the local clock
compared to a reference to understand just what its errors are, and
synthesize a "perfect" clock from it. The synthesized clock can remain
within a few microseconds (or better) of a reference timekeeper all the
time.

Isaac

Maybe that works if you leave the computer on all the time.

And that is exactly what NTP expects/needs.

I started
the ntpd daemon early in the morning and by late afternoon the time
was, once again, way the hell off. Since I only care one time, one
day a week what the time is I have set up crontab entries to do the
job.

It's also necessary to have a means to couple the output of the
disciplined clock to other apps that do things like run the clock on the
screen. Honestly, I'm not familiar with that; I've only used NTP to
synchronize things on embedded systems where we had control of all the
processes.

I do know that it can take quite a while (few dozen hours??) of
continuous operation before ntpd gets things figured out, and if the
host goes offline or sleeps it's necessary to start all over again. If
you read the man page, I think you'll see that there are ways to force a
faster, less precise, synch.

For more than you (probably) ever wanted to know about it, google up RFC
1305 and RFC 1128b.

ISaac