From owner-freebsd-questions Thu Apr 6 14:31:56 2000 Delivered-To: freebsd-questions@freebsd.org Received: from bingnet2.cc.binghamton.edu (bingnet2.cc.binghamton.edu [128.226.1.18]) by hub.freebsd.org (Postfix) with ESMTP id 5957137BA51 for ; Thu, 6 Apr 2000 14:31:38 -0700 (PDT) (envelope-from zzhang@cs.binghamton.edu) Received: from sol.cs.binghamton.edu (sol.cs.binghamton.edu [128.226.123.100]) by bingnet2.cc.binghamton.edu (8.9.3/8.9.3) with SMTP id RAA11505; Thu, 6 Apr 2000 17:31:30 -0400 (EDT) Date: Thu, 6 Apr 2000 15:06:17 -0400 (EDT) From: Zhihui Zhang To: Dan Nelson Cc: Dave Runkle , Freebsd Questions Subject: Re: Best Time Synch Utility In-Reply-To: <20000406130125.A19508@dan.emsphone.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thu, 6 Apr 2000, Dan Nelson wrote: > In the last episode (Apr 06), Zhihui Zhang said: > > On Thu, 6 Apr 2000, Dave Runkle wrote: > > > A really simple one (and it's in the ports) is 'rdate', but size > > > ain't everything. ;) The pkg is only 4k in size. It can be done via > > > cron, once daily, weekly, whatever, stuck in periodic, or even > > > executed from the command line, to set time on your machine or just > > > to check time. > > > > > > # /usr/local/sbin/rdate -s time.u.washington.edu > > > > Can you tell me how precision this command rdate can achieve (ms or us)? > > Thanks. > > Not even that precise :). rdate only has 1-second accuracy. There is > no reason to use rdate on FreeBSD at all, since ntpdate has millisecond > accuracy and comes with FreeBSD. > I am wondering how to keep a cluster of PCs in sync with each other within millisecond (loosely synchronized) even if the time of these PCs is not synchronized well with the outside world. This can be used in a timestamped concurrency control protocol. I wonder if ntpdate is good for this purpose. Thanks for any insight. -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message