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Re: NTPD unable to adjust local clock

From: Bill Hacker <wbh@xxxxxxxxxxxxx>
Date: Thu, 07 Apr 2005 05:42:30 +0800

Christopher Weimann wrote:

On 04/06/2005-07:52PM, Joerg Sonnenberger wrote:

Yes, I'm very well aware of it. I'm reading the original NTP papers and
will do some matth myself. Once we have done that, I'd like to add the
ability to record the frequency in a file, similiar to what DJB's program
[what ever it was named] does.

http://cr.yp.to/clockspeed.html ?

Isn't this a good alternative to ntp anyway?

So long as TCP/IP or UDP and cheap MB clocks are part of the equation, ntpd is not (cannot be) about absolute short-term accuracy (unfortunately).

What is does do is make it cheap (free) to sync boxen
that must agree with each other - 'accurately enough'
just by selecting the time sources and initial clock
settings carefully.

More critical needs - think currency arbitrage or
NASDAQ transaction time-stamping, may need better,
as NASA and the world's telephone companies certainly do,
and have always - see SONET/SDH and predecessors.

Those cost the very Earth to implement, distribute, and maintain.

GPS is the cheap-to-user option. As with most US-Military programs,
we may never know what it actually cost(s), other than 'not cheap'.


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