From owner-freebsd-hackers@FreeBSD.ORG Thu Jul 10 04:17:18 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E8BF9F49 for ; Thu, 10 Jul 2014 04:17:17 +0000 (UTC) Received: from cargobay.net (cargobay.net [162.220.58.155]) by mx1.freebsd.org (Postfix) with ESMTP id A47752D40 for ; Thu, 10 Jul 2014 04:17:16 +0000 (UTC) Received: from [10.53.97.25] (unknown [166.205.50.4]) by cargobay.net (Postfix) with ESMTPSA id 79ABC725 for ; Thu, 10 Jul 2014 04:00:28 +0000 (UTC) From: "Chad J. Milios" Mime-Version: 1.0 (1.0) Subject: Re: FreeBSD/Solaris dual-boot, problems with time (ntpd) Message-Id: <06FFA5E9-EAE1-4085-960A-4B06F313E961@ccsys.com> Date: Thu, 10 Jul 2014 00:07:13 -0400 References: In-Reply-To: To: "freebsd-hackers@freebsd.org" X-Mailer: iPhone Mail (11D257) X-Mailman-Approved-At: Thu, 10 Jul 2014 12:23:08 +0000 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.18 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Jul 2014 04:17:18 -0000 > On Jul 9, 2014, at 10:09 PM, Noel Hunt wrote: >=20 > I have a dual-boot machine, running ntpd in both OSes, but when > I switch from one OS to the other the time is wildly out. >=20 > Can someone explain what is going on please? >=20 > Noel Hunt Does your CMOS clock (aka BIOS) keep wallclock time or universal time? Eithe= r OS probably has the opposite idea. If you never boot DOS/Windows, your BIOS should probably keep universal time= . Each OS has a way to let it know if that is or is not the case. In FreeBSD, i= f any file exists at /etc/wall_cmos_clock then the kernel treats the CMOS cl= ock as the local time. If that file does not exist then the default is that t= he CMOS clock represents universal coordinated time (aka UTC). I don't use S= olaris enough to tell you its equivalent procedure from memory but it has th= e same toggle in there somewhere. (My knowledge of this is decades old. Can someone else confirm this is still= the canonical way to set this preference in FreeBSD?)=