From owner-freebsd-questions Thu Oct 1 03:55:45 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id DAA26895 for freebsd-questions-outgoing; Thu, 1 Oct 1998 03:55:45 -0700 (PDT) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from svr-a-02.core.theplanet.net (svr-a-02.core.theplanet.net [195.92.192.12]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id DAA26890 for ; Thu, 1 Oct 1998 03:55:38 -0700 (PDT) (envelope-from Robb.Andy@x-tension.com) Received: from mailhost.x-tension.co.uk ([195.92.139.2]) by svr-a-02.core.theplanet.net with esmtp (Exim 2.02SEGV #3) id 0zOgOE-0000Do-00 for freebsd-questions@FreeBSD.ORG; Thu, 1 Oct 1998 11:55:18 +0100 Received: by mailhost.x-tension.co.uk with Internet Mail Service (5.0.1457.3) id ; Thu, 1 Oct 1998 11:51:54 +0100 Message-ID: From: "Andy.Robb" To: "'freebsd-questions@FreeBSD.ORG'" Subject: training timeofday clock with ntpdate Date: Thu, 1 Oct 1998 11:51:51 +0100 X-Priority: 3 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.0.1457.3) Content-Type: text/plain Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Request: Please can you allow adjtime() calls to trim the system clock? Preferably, accumulate the adjustments in a file (probably ignoring large adjustments). This file could be read at bootup to trim the system clock. Background: I understand that the kernel includes code to trim the clock frequency when using xntpd. However, xntpd raises the ISDN line to our ISP every few minutes. I would like to be able to use the accumulated error from ntpdate (say) to train the kernel's clock to be within 0.5 sec/day (typically 0.1 sec/day) and use ntpdate just once a day. I know that Irix from SGI supports this kind of technique with both "timed" and "timeslave" daemons - albeit through special system calls. I have written programs using ICMP TIMESTAMP messages to synchronise both Linux (using adjtime) and HP-UX 9 systems (hacking the kernel) to a group of SGI systems that co-operated with timed. Many thanks for a great system, Andy Robb. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message