From owner-freebsd-questions@FreeBSD.ORG Thu Oct 26 20:01:18 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 10EC916A407 for ; Thu, 26 Oct 2006 20:01:18 +0000 (UTC) (envelope-from martin@dc.cis.okstate.edu) Received: from dc.cis.okstate.edu (dc.cis.okstate.edu [139.78.100.219]) by mx1.FreeBSD.org (Postfix) with ESMTP id A57A543D68 for ; Thu, 26 Oct 2006 20:01:17 +0000 (GMT) (envelope-from martin@dc.cis.okstate.edu) Received: from dc.cis.okstate.edu (localhost.okstate.edu [127.0.0.1]) by dc.cis.okstate.edu (8.13.3/8.13.3) with ESMTP id k9QK1H42072103 for ; Thu, 26 Oct 2006 15:01:17 -0500 (CDT) (envelope-from martin@dc.cis.okstate.edu) Message-Id: <200610262001.k9QK1H42072103@dc.cis.okstate.edu> To: freebsd-questions@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <72095.1161892877.1@dc.cis.okstate.edu> Date: Thu, 26 Oct 2006 15:01:17 -0500 From: Martin McCormick Subject: Leapseconds and zoneinfo X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Oct 2006 20:01:18 -0000 Several months ago, I rebuild the zoneinfo data bases on the freeBSD systems we have to be ready for the new Daylight Saving Time or Summer time rules. I got the leapseconds file and the North American data base and used zic to build a new version. The first time I did this, I included the leapseconds data base in to the command as in zic -L leapseconds northamerica What I got was a file slightly larger than the current version of localtime which, in the Central Time Zone is a copy of /usr/share/zoneinfo/America/Chicago. I didn't think much of the difference since it is a replacement for what was there and installed it. The local time was 23 seconds behind what it should be. There have been 23 leapseconds added since 1972, I think, so I figured we didn't need to have them in there. After recompiling the data base without the leapseconds, each system's UTC seconds perfectly matched the local time's seconds which is what is supposed to happen. Then, we come to today. I was experimenting with a FreeBSD system and noticed that the date;date -u commands yielded time stamps that were off by 23 seconds, but in the other direction. This time, I ran the command in the form you see above, with the leapseconds, and now that system's seconds perfectly match between UTC and Central time (CDT in Summer and CST) in Winter. Why would this one system which is an old 266 MHZ Pentium running FreeBSD 4.10 be different? Another old Pentium running FreeBSD4.7 needed the leapseconds removed before it gave the correct seconds for both UTC and Central time. I did verify that Chicago was the same file on the odd system as it was on all the normal ones, normal being that the seconds are correct for both UtC and local. So, for some reason, about 5 FreeBSD systems work properly without the leapseconds data base and one needed it. Why? It would stand to reason that all the systems need the leapseconds since that agrees with the rules for calculating correct time. Thank you. Martin McCormick WB5AGZ Stillwater, OK Systems Engineer OSU Information Technology Department Network Operations Group