[ntp:questions] Re: Correcting my time servers clock drift on Alpha ES40s / Tru64
Richard B. Gilbert
rgilbert88 at comcast.net
Sun Oct 23 15:41:05 UTC 2005
Tom Smith wrote:
> David L. Mills wrote:
>> Note the prefix of your log messages. It is not possible for the
>> kernel to simulate that. I conclude the source has been changed. I
>> have no problem at all with that, but the only way I can be
>> completely confident with help is with the unabridged version that
>> leaves here.
> The prefix on log messages comes strictly from the name of the executable
> (and its PID), not from the bits within it. It is used to show the source
> of the message. The version is shown in the log at the time (x)ntpd
> 20 Jul 17:40:44 xntpd: ntpd 4.0.98a Wed Oct 16 17:36:24 EDT 2002
> To the best of my knowledge, all versions of (x)ntpd announce their
> versions in this way.
> None of this has anything to do with the original question, of course,
> which was, essentially, "Why do my clocks that have no fixed reference
> not keep accurate time?".
Your clocks do not keep accurate time because they are not accurate!
They drift! The typical computer clock keeps time less well than the
typical cheap wristwatch. The wristwatch is designed to keep time and
people will not buy it if it does not keep time. The computer is not
designed as a time keeping device. Time keeping is an afterthought.
No configuration of ntpd that does not include an external source of
accurate time is likely to help you. That external source of accurate
time may be an internet connection, a GPS receiver, a dial-up phone call
to Automated Computer Time Service (ACTS) operated by the National
Institute of Standards and Technology (NIST), or a radio receiver
equipped to receive and decode the time signals broadcast by WWV or
WWVH (2.5, 5, 10, 15, and 20 MHz) or WWVB (60 KHz). All three of these
stations are operated by NIST. If you are rich, you can even purchase
your own atomic clock, have it calibrated by NIST and interface it to
Asking two inaccurate clocks to synchronize to each other may, if you
are lucky, cause them to keep the same time but in no way will it cause
them to keep accurate time!
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