[ntp:questions] Preffered OS for a GPS based stratum 1

Terje Mathisen terje.mathisen at hda.hydro.com
Sun Nov 2 15:20:55 UTC 2008

Unruh wrote:
> clock, and how much is inherent I do not know. But since the clock on Linux
> is 1usec quantization and the accuracy of my gps is 1 usec, I figure this
> is about as good as it gets. I doubt that you can get consistant reading of
> the cpu clock even from the kenrel to better than about 1us, whether on
> linux or on BSD.

Famous last words? :-)

PHK has setup several FreeBSD-based refclocks that measure out well 
below the 1 us level, i.e. take a look at:


A quote from that page:

"Current status is that I can track my GPS receiver into a band less 
than 150 nsec wide around true UTC. This is an order of magnitude better 
than any other UNIX system I know of. My performance is probably even 
better than that, but I have not had much chance to validate it yet."

- <Terje.Mathisen at hda.hydro.com>
"almost all programming can be viewed as an exercise in caching"

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