[ntp:questions] stupid, simple question about precision

Richard B. Gilbert rgilbert88 at comcast.net
Mon Nov 20 22:11:37 UTC 2006


David J Taylor wrote:
> Simple Simon wrote:
> []
> 
>>My understanding is the best accuracy I might get, on a generic PC
>>clock, is about 0.050 ms--and that's with SSP and the kernel clock.
> 
> 
> My really old 133MHz Pentium PC with FreeBSD and a PPS source (with an 
> incomplete view of the sky) does a little better than than.  I'm sure more 
> modern hardware and a better-positioned GPS antenna would do substantially 
> better.
> 
>   http://www.david-taylor.myby.co.uk/mrtg/pixie_ntp.html
> 
>   http://www.david-taylor.myby.co.uk/ntp/FreeBSD-GPS-PPS.htm
> 
> Cheers,
> David 
> 
> 

I haven't tried it with a PC but a ~10 year old Sun Ultra 10 with a 440 
MHz processor and Solaris 8 keeps time within a couple of microseconds. 
   I do have a good view of the sky.  Something blazingly fast with a 
lower interrupt latency might do still better but my modest hardware 
meets and exceeds my very modest needs.





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