From owner-freebsd-stable Mon Nov 20 8:40:50 2000 Delivered-To: freebsd-stable@freebsd.org Received: from gw-nl1.origin-it.com (gw-nl1.origin-it.com [193.79.128.34]) by hub.freebsd.org (Postfix) with ESMTP id D134E37B4C5 for ; Mon, 20 Nov 2000 08:40:42 -0800 (PST) Received: from mail.de.origin-it.com (localhost.origin-it.com [127.0.0.1]) by gw-nl1.origin-it.com with ESMTP id RAA15296; Mon, 20 Nov 2000 17:40:34 +0100 (MET) (envelope-from Helge.Oldach@de.origin-it.com) Received: from smtprelay-de1.origin-it.com(172.16.188.53) by gw-nl1.origin-it.com via mwrap (4.0a) id xma015293; Mon, 20 Nov 00 17:40:34 +0100 Received: from mailhub.de.origin-it.com (mailhub.de.origin-it.com [172.16.189.20]) by mail.de.origin-it.com (8.9.3/8.8.5-1.2.2m-19990317) with ESMTP id RAA26338; Mon, 20 Nov 2000 17:40:33 +0100 (MET) Received: from galaxy.de.cp.philips.com (galaxy.de.cp.philips.com [130.143.166.29]) by mailhub.de.origin-it.com (8.11.1/8.11.1/hmo23oct00) with ESMTP id eAKGeUY00686; Mon, 20 Nov 2000 17:40:31 +0100 (CET) (envelope-from Helge.Oldach@de.origin-it.com) Received: (from hmo@localhost) by galaxy.de.cp.philips.com (8.9.3/8.9.3/hmo14aug98) id RAA15704; Mon, 20 Nov 2000 17:40:29 +0100 (MET) Message-Id: <200011201640.RAA15704@galaxy.de.cp.philips.com> Subject: Re: Dedicated disks (was: Dangerously Dedicated) In-Reply-To: <200011200019.RAA16004@harmony.village.org> from Warner Losh at "Nov 19, 2000 5:19:43 pm" To: imp@village.org (Warner Losh) Date: Mon, 20 Nov 2000 17:40:28 +0100 (MET) Cc: grog@lemis.com, samz@oz.net, stable@FreeBSD.ORG From: Helge Oldach X-Address: Atos Origin, Billstrasse 80, D-20539 Hamburg, Germany X-Phone: +49 40 7886 464, Fax: +49 40 7886 235, Mobile: +49 172 4515513 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Warner Losh: >In message <20001120095100.G58333@echunga.lemis.com> Greg Lehey writes: > As far as I know, there has been no decision to remove dedicated mode. >: I for one would strongly oppose it. Arguments about bootstraps and >: BIOS are bogus: on a dedicated machine, you only need a bootstrap on >: the boot disk, so any additional disks can always be dedicated. But >: to answer your question: if you have to change from dedicated to a >: Microsoft compatible layout, yes, you'll have to rebuild all your file >: systems. > >No it isn't bogus. You can't boot off a DD disk on some machines >because the MBR is too bogus for the BIOS to cope with. > >The problem with DD is that we put a bogus MBR onto the disk. All >that is necessary to fix it would be to put a non-bgous MBR onto the >disk. If I'm not mistaken that's a contradiction. PC BIOS architecture demands that the first cylinder is not to be used. But obviously DD mode will use it. So what do you put in a non-bogus partition table? If it says the first slice starts at cylinder 0 you still have a broken MBR. If it says it starts at cylinder 1 you are stuck with inconsistency, as cylinder 0 is in fact in use. Seems to me that DD's bogus MBR can't be properly and consistently fixed. Helge To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message