[ntp:questions] best gps receiver for time synchronization

David Woolley david at ex.djwhome.demon.co.uk.invalid
Fri Mar 13 00:11:18 UTC 2009

> My plan is to read GPS messages in my own application and use them to
> discipline a simulated software clock with Windows high performance
> counter. This way I can avoid Windows scheduling issues.

Seems to me that you want to implement your application in-process with 
ntpd or equivalent.
> Now I am not sure how to get GPS messages as soon as they come in. Is
> there a way to do it through interruption? Polling doesn't sound good
> to me. Can somebody point me to some references please?

Interrupts from PCI or ISA cards, or motherboard equivalents.  Under no 
circumstances use USB.  You should use the PPS outputs on the reference 
clocks.  You will need to run at a hard real time priority.  You may 
need special serial/parallel drivers, if Windows doesn't support 
interrupts for modem controls.

Polling will just synchronise you to some multiple of the timer tick.

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