[aklug] Re: ntp and freebsd?

On Thu, Mar 15, 2012 at 6:49 PM, Royce Williams <royce@tycho.org> wrote:
> Dr. Anderson's claim is built on the idea that the FreeBSD kernel
> supports nanosecond time precision. =A0I do not know enough about it to
> verify whether or not Linux is truly lacking in nanosecond-level timing
> for this purpose. =A0I found multiple people saying that online, but no
> authoritative source.
>
> With Stratum 1, you're building an NTP server directly attached to a
> high-precision time source, for which millisecond precision isn't
> precise enough, so just running an NTP daemon isn't sufficient for what
> he's trying to do.
>
> Part of the reason that FreeBSD is so well-equipped for high-precision
> time is because a famous FreeBSD guy, Poul-Henning Kamp, is a huge time
> geek, and he did a bunch of work to make FreeBSD recision-time-friendly.
> He notices when *GPS satellites* have time that's off by less than a
> millisecond.
>
> http://people.freebsd.org/~phk/
>
> Royce
>

I don't think I've ever seen a Stratum 1 box in my life...

I've always used the ntp.org server (ntp in debian) along with a GPS
for systems that couldn't retrieve time reliably in other ways. I
really like this approach.. I typically use said systems to serve out
a local broadcast time as well.

I can't even imagine what hardware it would take to get nanosecond
precision from Boulder, CO.

- Shane
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Received on Fri Mar 16 15:16:51 2012