[ntp:questions] Re: How application get precise time from Win NT/XP system time that synchronies to NTP

Danny Mayer mayer at gis.net
Thu Mar 31 03:20:23 UTC 2005


At 11:00 AM 3/30/2005, Roger Chou wrote:
>Martin,
>
>I would like to try polls Windows 2000/ XP system time. Can you tell me how
>to do it? Only poll once every tick, see if I can get 1ms resolution?
>
>Thanks,
>
>Roger Chou

Please don't send me private email on this. The discussion belongs
here.

I think you really don't understand. Ask yourself this question: How long
does it take to request the time and get the answer back? On Windows
that time is not determinable, it depends on too many variables. Once the
error overwelms the measurement it's not even clear anymore what's
getting measured. You cannot possibly poll every tick. You can only get
the accuracy that you are asking about by throwing hardware at the
problem, and very expensive hardware at that. Does this application have
that kind of need? If you don't understand this you need to take a basic
course in experimental physics where this kind of thing is taught as part
of how to measure things.

You really need to tell us what it is that you are trying to do in a way
that it makes sense to an outsider. There may be a better solution.

Danny





More information about the questions mailing list