From owner-freebsd-hackers@FreeBSD.ORG Tue Aug 1 12:16:58 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id F3DC116A521 for ; Tue, 1 Aug 2006 12:16:57 +0000 (UTC) (envelope-from amdmi3@mail.ru) Received: from mx27.mail.ru (mx27.mail.ru [194.67.23.65]) by mx1.FreeBSD.org (Postfix) with ESMTP id 19F8843D79 for ; Tue, 1 Aug 2006 12:15:04 +0000 (GMT) (envelope-from amdmi3@mail.ru) Received: from [213.148.29.33] (port=62808 helo=nexii.panopticon) by mx27.mail.ru with esmtp id 1G7t9L-00059u-00; Tue, 01 Aug 2006 16:15:03 +0400 Received: from hades.panopticon (hades.panopticon [192.168.0.2]) by nexii.panopticon (Postfix) with ESMTP id AA73A1705C; Tue, 1 Aug 2006 16:15:03 +0400 (MSD) Received: by hades.panopticon (Postfix, from userid 1000) id 43C7F417F; Tue, 1 Aug 2006 16:14:59 +0400 (MSD) Date: Tue, 1 Aug 2006 16:14:59 +0400 From: Dmitry Marakasov To: Dan Nelson Message-ID: <20060801121459.GA81372@hades.panopticon> Mail-Followup-To: Dan Nelson , freebsd-hackers@freebsd.org References: <20060731203213.GA75233@hades.panopticon> <20060731205043.GD63872@dan.emsphone.com> MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <20060731205043.GD63872@dan.emsphone.com> User-Agent: Mutt/1.5.12-2006-07-14 Cc: freebsd-hackers@freebsd.org Subject: Re: absolute vs. relative offsets in disklabel X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Aug 2006 12:16:58 -0000 * Dan Nelson (dnelson@allantgroup.com) wrote: > > Recent `disklabel differences FreeBSD, DragonFly' thread gave me a > > thought - why do we have absolute offsets in disklabel? AFAIK, on > > NetBSD and OpenBSD, label is not necessarily located `near' > > filesystems stored in it's partitions - and even disklabel utility > > shows absolute offsets (with 'c' covering entire device). FreeBSD, > > however, seem to step far away from that standart - 8 partitions > > instead of 16, label located in the beginning of a partition, > > bsdlabel shows relative offsets. Now I wonder if there are any > > reasons for offsets to be actually absolute? There are many weighty > > arguments for relative offsets: > I asked this question a few years ago after having problems dd'ing a > FreeBSD installation from one disk to another, and the answer was "it's > always been that way" :) It shouldn't be too hard to have the code > autodetect whether the offsets are relative or absolute by looking at > what the 'c' partition's offset is. The only problem seem to be that older FreeBSD versions won't be able to use modified labels. -- Best regards, Dmitry mailto:amdmi3@mail.ru