timed problems?

[Roy Smith]

In <103 at bohra.cpg.oz> als at bohra.cpg.oz (Anthony Shipman) writes:
> I have just set up three machines to run with synchronised clocks using
> /etc/timed [...] Does anyone have any experience they would like to impart?

	Having used to run timed, I would say the best advice is to chuck
it and use ntpd instead.  If you are connected to the Internet, you can
keep your clock within a fraction of a second of The Right Time, and if
you're not, at least you can keep all of your machines on an ethernet
within a very small fraction of a second of each other.

	The real problem with timed is that you have no control over who
ends up being the master clock.  On our net, it usually ended up being an
Iris in another building 4 blocks away that I had no control over, and
which generally had its clock set to some totally random time.  I
eventually got pissed at having people come into my office complaining
that their $12 quartz-and-plastic Casio wristwatch kept better time than
their $5000 workstation.

	Actually, before we even ran timed, I used to just have each of our
diskless workstations run rdate when they booted.  This at least started
them all out with a clock that was within about a second of each other,
which doesn't approach the precision you get with ntpd, but may be good
enough for most purposes.  Most of our machines are 4-Meg diskless
workstations, on which memory is a critical resource.  I havn't yet decided
if running ntpd on all of them is worth it, but the choice is between ntpd
and rdate-on-bootup-then-freerun, not between ntdp and timed.
--
Roy Smith, Public Health Research Institute
455 First Avenue, New York, NY 10016
roy at alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
"Arcane?  Did you say arcane?  It wouldn't be Unix if it wasn't arcane!"