Network Time Server

[Georg S. Nikodym]

In article <k2.671438714 at woodstock>, k2 at bl.physik.tu-muenchen.de (Klaus Steinberger) writes:
> rbraun at spdcc.COM (Rich Braun) writes:
> 
> >I recently brought up timed on a couple of SCO Unix systems and an RS-6000,
> >hoping to have a reliable, synchronized time source on my TCP/IP LAN.
> >Instead, I have a bunch of synchronized systems which lose about a
> >minute per day.  The SCO documentation doesn't say anything about how
> >one sets up a reference time source; timed only serves the purpose of
> >synchronization, and there's no way of telling it which system is "the"
> >reference source.

Yes there is.  In the file "/etc/tcp" (which is linked to /etc/rc2.d/Snntcp)
you have a line that starts timed.  Timed invoked with the -M option
will _allow_ that time daemon to become a "master" should the running master
go away.  If you only want one master, then only use -M on one of the timeds
(ignoring the fact the all the other clocks on the net will get stupid when
you reboot this machine).  You can use the "timedc" command to make queries
of the timed system (like finding out who is master, what the time difference
is between 2 nodes, etc).

> >How do I solve this problem?  I'm working for a company whose business
> >is selling clocks, so needless to say, inaccurate clocks are particularly
> >annoying to me ;=)

There is another problem here, however, and that is the problem of the
time clock hardware on PCs today.  I have never seen one keep accurate
time for any duration.  There's further goo in the works because UNIX
keeps its own time, which depending on how much your hardware beats on
the kernel (which in this case is a fair bit), it loses time as well.
The solution to this is to have one machine (which would also be the
master timed) with a modem call one of the atomic clocks on the
continent.  I've seen one for XENIX that called a naval observatory in
Washington to get the time, the program would then run something
like "setclock(ADM)" which sets your hardware clock.  Run
this on a daily basis and you're set.

> timed is the best method to get synchronized funny clocks.
> 
> Instead it's better to use ntp. (Network time protocol)
> It can synchronize to a master clock. The master clock can be a stable
> quartz clock, or even better a radio time standards.

You'll probably be able to get this from the free BSD sources (don't
flame, I guessing ;-)  Personally, not being inclined to re-invent wheels,
I'd use the timed you already have.

> There are many servers for ntp in the internet, and it's possible to
> get a synchronized clock with a maximum error of 10 milliseconds.
> 
> Look into comp.protocols.time.ntp for more information.

True, though you may not be able to get to them via phone... :-(
-- 
Georg S. Nikodym  -  466-1079	|  "Eastern Germany's defunct legal system
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