[ntp:questions] stupid, simple question about precision

Simple Simon ssimon at domain.invalid
Mon Nov 20 22:46:16 UTC 2006


rgilbert88 at comcast.net wrote...
> 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.

Is your GPS directly updating your hardware, or is your SPARC an NTP 
client of a Stratum 1 timeserver connected to the GPS, or... ?

-- 
Taxes are not "punishment for success".  Nor are they "theft".  Taxes 
are a royalty paid commensurate to the economic benefit obtained from 
a shared socio-economic system.

"Those who gain the benefit should also bear the disadvantage." 
                                                   - Common Law maxim




More information about the questions mailing list