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Re: [gpsd-dev] Clarifications needed for the time-service HOWTO

From: Gary E. Miller
Subject: Re: [gpsd-dev] Clarifications needed for the time-service HOWTO
Date: Mon, 21 Oct 2013 13:57:54 -0700

Yo Eric!

On Mon, 21 Oct 2013 16:45:39 -0400
"Eric S. Raymond" <address@hidden> wrote:

> The public documentation insists that Stratum 1 servers are supposed 
> to have fixed and latency-compensated paths.  I totally believe you
> when you say people screw this up, but that doesn't seem like a good
> reason to ignore the specification.

What spec do you refer to?

> Maybe the thing to do is keep the specification in the overview and
> later note that there are incompetent Stratum 1s that get it wrong.

Remember that anyone that follows this document will be a stratum 1.
How many ill bother to get their fudge right?  How many will be on 
cable modems with horribly random aaysmetric latencies?  How many
will be playing games or compiling Chrome while their server is up?

> Are Ask Bjørn Hansen and his crew at the NTP Pool crew doing a good 
> job of kicking bogus Stratum 1s off their list?

I've tried several ntp pools.  Good enough to set your clock to the
second, but not better than that.  And given that they are random, one
day you may get a good one nearby, and next day and awefull one 10,000
miles away.

> If so, that's a thing to note in the HOWTO.  If they're doing a
> terrible job, that would be an even more important thing to note.

Yes, was on my list to mention.  I would take a more nuanced postition.
Since most cell phones have trouble getting the minute correct, ntp
pools are great for them.  Try it, you be shocked at how bad your cell
phone clock is.  

OTOH, when I'm working with a properly disciplined uSec local PPS my
clock my needs are much different.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701
        address@hidden  Tel:+1(541)382-8588

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