From owner-freebsd-questions@FreeBSD.ORG Sat Jan 1 00:34:11 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C93ED106573A for ; Sat, 1 Jan 2011 00:34:11 +0000 (UTC) (envelope-from freebsd-questions@m.gmane.org) Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mx1.freebsd.org (Postfix) with ESMTP id 533E68FC1E for ; Sat, 1 Jan 2011 00:34:11 +0000 (UTC) Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1PYpQ9-0003As-DH for freebsd-questions@freebsd.org; Sat, 01 Jan 2011 01:34:09 +0100 Received: from pool-173-79-85-36.washdc.fios.verizon.net ([173.79.85.36]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 01 Jan 2011 01:34:09 +0100 Received: from nightrecon by pool-173-79-85-36.washdc.fios.verizon.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 01 Jan 2011 01:34:09 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-questions@freebsd.org From: Michael Powell Followup-To: gmane.os.freebsd.questions Date: Fri, 31 Dec 2010 19:37:10 -0500 Lines: 54 Message-ID: References: <20101229120038.3DFB0106591A@hub.freebsd.org> <20101230133126.O36121@sola.nimnet.asn.au> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: pool-173-79-85-36.washdc.fios.verizon.net Subject: Re: a new hard-drive in a 2y/o laptop 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: Sat, 01 Jan 2011 00:34:11 -0000 Ian Smith wrote: > In freebsd-questions Digest, Vol 343, Issue 5, Message: 10 > On Tue, 28 Dec 2010 11:02:45 -0500 Chris Brennan > wrote: > > On Tue, Dec 28, 2010 at 2:23 AM, Michael Powell > > wrote: > > > > > Try zeroing out the mbr: > > > > > > Boot a LiveFS CD, then at a root prompt do: > > > > > > sysctl kern.geom.debugflags=16 and: > > > > > > dd if=/dev/zero of=/dev/adx oseek=1 bs=512 count=1 > > > > > > where x equals your drive number. This will zero out any old MBR. > > Er, no, Mike. The MBR is in sector 0 of the disk; that would zero out > sector 1 as oseek=1 skips over sector 0. What's in sector 1 depends on > how/whether the disk is sliced. In a 'dangerously dedicated' (unsliced) > disk like a memory stick perhaps, this would usually be /boot/boot1 and > include the bsdlabel. In a sliced disk, sectors 1 to 62 are typically > unused, the first slice usually starting at sector 63. > > t23% fdisk -s ad0 > /dev/ad0: 232581 cyl 16 hd 63 sec > Part Start Size Type Flags > 1: 63 8385867 0x0b 0x00 > 2: 8385930 125821080 0xa5 0x80 > 3: 134207010 33543342 0xa5 0x00 > 4: 167750730 66685815 0xa5 0x00 > > If you really want to zero out sector 0, leave out the oseek (or use > oseek=0) - but you're better off using 'fdisk -Bi' to init a new disk. > Yes - true enough. Was thinking partition table and typed 'mbr'. > Mmm .. it's not clear from Chris' original message exactly what he did. In my case, a temporary replacement disk had FreeBSD 6.2 on it. Something changed wrt to disklabeling on the way to 8-Release and the old 6.2 being present created a situation where that region on the disk was invisible to the new labeling and wouldn't write out. A new install of 8-Release (sysinstall) would error out with the same message as Chris when it came to the point of writing out to the disk. For me, the above 2 commands fixed my situation. Even though his error is the same, I think his problem may be different from mine. -Mike [snip]