[ntp:questions] A question
David Woolley
david at ex.djwhome.demon.co.uk.invalid
Fri May 2 21:50:51 UTC 2008
Bruno Cocciaro wrote:
> Are you meaning that the easist way is to keep my pc clock synchronized (for
> example using Dimension 4) and send the enquiry to my pc clock ?
Note, if you are using Windows, the time resolution is rather limited
(about 16ms, but maybe better with multimedia timers on). If you are
close enough to a good time server that you can directly read the time
more accurately than the resolution of the Windows clock, it may be
better to access it directly, but given the questions you ask, you will
need the services of a programmer. Tell them to read the TSC before
making the request and subtract off half the change in its value,
converted to appropriate units, between the request and the response.
Don't use Dimension 4, use the reference implementation of ntpd. As far
as I know, Dimension 4 isn't open source, so it will be difficult to
work out how it works, but it is not going to be better than the
reference implementation, and is probably worse.
If you need better than 16ms, you might be able to query a copy of the
reference implementation of ntpd, running on the same machine, as that
keeps time to better than 16ms, but you would probably be better running
a Unix/Free BSD/Linux machine on the same LAN segment.
>
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