Bill Studenmund wrote:
> On Wed, 25 Mar 1998, Jonathan Stone wrote:
> 
> > >First I thought the problem was that GENERIC kernels do not have options
> > >NTP turned on.  Now I have a custom kernel with that option and I am seeing
> > >the same problem other people have reported:  NTP thinks it's working, but
> > >it isn't fixing the local clock.
> >   ...
> > >Anybody got any ideas for where the problem is?
> > 
> > the problem is that the Mac hardware has a priority inversion: it puts
> > the serial port at higher priority than the clock.
> > 
> > This causes macbsd to lose clock-tick interrupts (up to 5%), killing NTP.
> > here is just _no_way_ NTP can handle sustained loss of clock ticks.
> > It creates about 3 orders of magnitude more jitter than NTP is
> > designed to handle.

[snip]
 
> > That's  a Definitive Answer of the cause of the problem.
> > I thought it was going to be in the release notes for 1.3.1.
> 
> Doh! So did I. We should probably talk to Colin about it. :-(

Oops.  I thought I had.  I guess it managed to get buried on my TODO list.
I'll see if I can get to it this weekend and maybe we can make the 1.3.2
release notes.

Later.

-- 
Colin Wood                                 cwood@ichips.intel.com
Component Design Engineer - MD6                 Intel Corporation
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I speak only on my own behalf, not for my employer.