[ntp:questions] help with setting up NTP on windows with a USB GPS

David J Taylor david-taylor at blueyonder.not-this-bit.nor-this-part.co.uk.invalid
Sun Dec 6 19:48:34 UTC 2009


"David Woolley" <david at ex.djwhome.demon.invalid> wrote in message 
news:hfgvt5$g6f$1 at news.eternal-september.org...
> David J Taylor wrote:
>
>> Stated requirement:
>>
>>  - around 1 millisecond (on Window 2000 or XP IIRC).
>>
>> Observed performance examples:
>
> These don't tell you the jitter due to the scheduling of the application 
> program and interrupt latencies from the real world events to the point 
> where the code tries to read the time.

Of course the application has to be well-designed and use appropriate 
interactions with the OS - that goes without saying.  NTP can measure 
better than a millisecond on Windows.  As the application is an existing 
Windows one, the OS is fixed, and the challenge is then to provide the 
best timekeeping within the imposed constraints.

Cheers,
David 




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