From owner-freebsd-questions@FreeBSD.ORG Fri Mar 31 20:07:39 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 D14BC16A423 for ; Fri, 31 Mar 2006 20:07:39 +0000 (UTC) (envelope-from flowers@users.sourceforge.net) Received: from pd5mo3so.prod.shaw.ca (shawidc-mo1.cg.shawcable.net [24.71.223.10]) by mx1.FreeBSD.org (Postfix) with ESMTP id BD73143D45 for ; Fri, 31 Mar 2006 20:07:36 +0000 (GMT) (envelope-from flowers@users.sourceforge.net) Received: from pd3mr5so.prod.shaw.ca (pd3mr5so-qfe3.prod.shaw.ca [10.0.141.12]) by l-daemon (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with ESMTP id <0IX000A15D632080@l-daemon> for freebsd-questions@freebsd.org; Fri, 31 Mar 2006 13:06:03 -0700 (MST) Received: from pn2ml1so.prod.shaw.ca ([10.0.121.145]) by pd3mr5so.prod.shaw.ca (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with ESMTP id <0IX000IZFD63WEB0@pd3mr5so.prod.shaw.ca> for freebsd-questions@freebsd.org; Fri, 31 Mar 2006 13:06:03 -0700 (MST) Received: from aldebaran.local ([68.144.98.157]) by l-daemon (Sun ONE Messaging Server 6.0 HotFix 1.01 (built Mar 15 2004)) with SMTP id <0IX00074WD63FUJ0@l-daemon> for freebsd-questions@freebsd.org; Fri, 31 Mar 2006 13:06:03 -0700 (MST) Received: (qmail 68632 invoked by uid 1001); Fri, 31 Mar 2006 20:06:03 +0000 Date: Fri, 31 Mar 2006 13:06:02 -0700 From: Danny MacMillan To: freebsd-questions@freebsd.org Message-id: <20060331200602.GA68298@aldebaran.local> MIME-version: 1.0 Content-type: text/plain; charset=unknown-8bit Content-transfer-encoding: 8BIT Content-disposition: inline User-Agent: Mutt/1.4.2.1i Subject: Can FreeBSD safely use a (un-booted from) drive that is invisible to the BIOS? 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: Fri, 31 Mar 2006 20:07:39 -0000 Hi, I have a machine with the following two drives (as listed in dmesg): ad0: 12427MB at ata0-master UDMA33 ad2: 76319MB at ata1-master UDMA33 ad0 is the boot drive. It is recognized by the BIOS, obviously, and has been in the machine for some years. ad2 is a new drive I just added to the machine yesterday. It is not visible to the BIOS at all. If anyone can posit a reason it would not be visible to the BIOS, I would like to know the answer. The BIOS supports LBA and ad0 is more than 8GB so it wouldn't appear to be the 8GB limit, and the next limit I am aware of is comfortably larger than 76GB. At any rate ... it is not visible to the BIOS, but it is visible to FreeBSD. Since I'm not booting from the drive, I think it shouldn't matter ... but when I use Fdisk from sysinstall I get the following familiar error message: |WARNING: A geometry of 155061/16/63 for ad2 is incorrect. Using ¦ ¦a more likely geometry. If this geometry is incorrect or you ¦ ¦are unsure as to whether or not it's correct, please consult ¦ ¦the Hardware Guide in the Documentation submenu or use the ¦ ¦(G)eometry command to change it now. ¦ ¦ ¦ ¦Remember: you need to enter whatever your BIOS thinks the ¦ ¦geometry is! For IDE, it's what you were told in the BIOS ¦ ¦setup. For SCSI, it's the translation mode your controller is ¦ ¦using. Do NOT use a ``physical geometry''. | Since I don't actually know what the BIOS thinks the geometry is, I got cold feet and decided to ask the list. I don't =think= it should matter, since the BIOS shouldn't ever touch the disk, at least as far as my understanding goes. I do have one concern. This drive was purchased more or less to act as an emergency backup of the drive that's already in there. If ad0 ever fails, ad2 drive will have to be put in a new machine whose BIOS recognizes it in order to boot. If I accept the mystery geometry for the drive today, will I later face a problem where the BIOS disagrees and the drive will be unbootable? Thank you for your kind attention. -- Danny MacMillan