From owner-freebsd-questions@FreeBSD.ORG Sun Mar 19 12:34:14 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 D8DC816A401 for ; Sun, 19 Mar 2006 12:34:14 +0000 (UTC) (envelope-from harlan@everett.org) Received: from minnie.everett.org (minnie.everett.org [66.220.13.228]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9FA8443D46 for ; Sun, 19 Mar 2006 12:34:14 +0000 (GMT) (envelope-from harlan@everett.org) Received: from minnie.everett.org (localhost [127.0.0.1]) by minnie.everett.org (Postfix) with ESMTP id 4390354827; Sun, 19 Mar 2006 04:34:13 -0800 (PST) To: Chuck Swiger In-reply-to: <441D4DFB.8030600@mac.com> References: <20060319120349.CA86E54821@minnie.everett.org> <441D4DFB.8030600@mac.com> Comments: In-reply-to Chuck Swiger message dated "Sun, 19 Mar 2006 07:26:35 -0500." X-Mailer: MH-E 7.4.2; nmh 1.2; XEmacs 21.4 (patch 19) Mime-Version: 1.0 (generated by tm-edit 1.8) Content-Type: text/plain; charset=US-ASCII Date: Sun, 19 Mar 2006 04:34:13 -0800 From: Harlan Stenn Message-Id: <20060319123414.4390354827@minnie.everett.org> Cc: freebsd-questions@freebsd.org Subject: Re: CF disk slices? 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: Sun, 19 Mar 2006 12:34:14 -0000 > Harlan Stenn wrote: > > Can one put multiple slices on a CF disk? > Sure. Most BIOSes will treat a CF flash much like they would a USB > device, and they'll be happy to see a MBR. Hmmm - I can see the slices on a FreeBSD-4 machine but not on a FreeBSD-5 machine. > > I ran fdisk on one machine > > and was able to carve up a CF disk with 4 slices (I want to boot one of > > 4 different OSes on a soekris system). There are other systems that > > seem to indicate that a CF disk can only have 1 slice on it. > Hmm. You are perhaps not aware that flash memory can only do a relatively > limited number of writes before failing (10K to perhaps 50K, if you've got a > fancy CF card with write leveling and/or spare sectors)...? Yup, and my plan is to slice the card, do a dd dump of a bootable OS to one partition, and then do a dd dump of another bootable OS to the other partions. > Installing and updating multiple operating systems is contraindicated > on such hardware not because it is not possible to do, but because the > CF won't last very long under such a usage profile. I'm even planning to netboot grub for this box so I can control which OS boots without writing to the card. > You should configure a CF-based system to operate with the filesystems > mounted read-only most of the time, or at least turn off updating > atime information. That's the way they are set up - I even think the normal OS on that copies things like root's homedir to a memory filesystem during the boot and then mounts that somewhere for "live" use just to avoid writing to the drive. My goal is to have the CF disk be used in case I cannot do a netboot. H