Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758027AbZAEABt (ORCPT ); Sun, 4 Jan 2009 19:01:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751524AbZAEABl (ORCPT ); Sun, 4 Jan 2009 19:01:41 -0500 Received: from hawking.rebel.net.au ([203.20.69.83]:41571 "EHLO hawking.rebel.net.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750788AbZAEABl (ORCPT ); Sun, 4 Jan 2009 19:01:41 -0500 Message-ID: <49614DD8.7070707@davidnewall.com> Date: Mon, 05 Jan 2009 10:31:28 +1030 From: David Newall User-Agent: Thunderbird 2.0.0.12 (X11/20080227) MIME-Version: 1.0 To: Chris Adams CC: linux-kernel@vger.kernel.org Subject: Re: Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009 References: <3ae3aa420901021125n1153053fsdf2378e7d11abbc0@mail.gmail.com> <20090102210430.49649261@diego-desktop> <495E7849.4030706@shaw.ca> <495F0672.6020708@davidnewall.com> <8752a8760901022237r75d408b3i74c703c8ac2d4597@mail.gmail.com> <496076A9.7030907@davidnewall.com> <4960897D.5030603@davidnewall.com> <4961432A.80509@davidnewall.com> <20090104232534.GB1297917@hiwaay.net> In-Reply-To: <20090104232534.GB1297917@hiwaay.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1324 Lines: 29 Chris Adams wrote: > Once upon a time, David Newall said: > >> No. Exactly the contrary. I'm saying that through use of zoneinfo, for >> example, no kernel support is required for leap seconds. And! this >> provides correct results for seconds-between two dates. >> > > Again: zoneinfo provides offset from UTC. Leap seconds are changes in > UTC itself, not time zones, so zoneinfo can't handle that. > Yes, but zoneinfo ALSO provides support for leap seconds. Do read man zic for specific details. > Please go read Google, Wikipedia, and NTP lists. I think you particularly mean NTP. I think your reasoning is that because NTP's timestamp doesn't include leap seconds, and because we all like to use NTP to synchronise our clocks, Linux has to make up the difference. But there is an alternative; which is for the NTP client to insert those missing leap seconds, which number it can get from zoneinfo. Epoch remains the start of 1978; seconds between any two dates included leap-seconds and no special kernel support is required. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/