From owner-freebsd-hackers Sun Mar 31 12:26:41 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from rover.village.org (rover.bsdimp.com [204.144.255.66]) by hub.freebsd.org (Postfix) with ESMTP id 10DB437B41C for ; Sun, 31 Mar 2002 12:26:38 -0800 (PST) Received: from harmony.village.org (harmony.village.org [10.0.0.6]) by rover.village.org (8.11.3/8.11.3) with ESMTP id g2VKQai46368; Sun, 31 Mar 2002 13:26:36 -0700 (MST) (envelope-from imp@village.org) Received: from localhost (warner@rover2.village.org [10.0.0.1]) by harmony.village.org (8.11.6/8.11.6) with ESMTP id g2VKQYf51542; Sun, 31 Mar 2002 13:26:35 -0700 (MST) (envelope-from imp@village.org) Date: Sun, 31 Mar 2002 13:25:49 -0700 (MST) Message-Id: <20020331.132549.127506348.imp@village.org> To: dp@penix.org Cc: hackers@FreeBSD.ORG Subject: Re: GPS time. From: "M. Warner Losh" In-Reply-To: References: X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In message: Paul Halliday writes: : I just connected my gps (garmin gps III plus) to my serial port : and realized that simply cat'ing cua0 displays date/time/position of the : unit. (neato). Anyway, how accurate would it be to use the time from this : output for ntp as opposed to my current setup using ntp servers. Generally the output time from these receivers via the serial port isn't very good from a precise time keeping point of view. There's about 10ms of variation in the reported time, which makes them very very noisy for the sort of work that ntp does. For a local network, it shouldn't be too bad, but expect to see a lot of strange things happen because the error can be so large. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message