From owner-freebsd-questions@FreeBSD.ORG Wed Mar 10 09:24:04 2004 Return-Path: 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 555FE16A4CE for ; Wed, 10 Mar 2004 09:24:04 -0800 (PST) Received: from falcon.midgard.homeip.net (h201n1fls24o1048.bredband.comhem.se [212.181.162.201]) by mx1.FreeBSD.org (Postfix) with SMTP id 8DEDA43D3F for ; Wed, 10 Mar 2004 09:24:02 -0800 (PST) (envelope-from ertr1013@student.uu.se) Received: (qmail 53992 invoked by uid 1001); 10 Mar 2004 17:24:01 -0000 Date: Wed, 10 Mar 2004 18:24:00 +0100 From: Erik Trulsson To: Jason Dictos Message-ID: <20040310172400.GA53950@falcon.midgard.homeip.net> Mail-Followup-To: Jason Dictos , 'Sergey 'DoubleF' Zaharchenko' , Dan Nelson , "''freebsd-questions@freebsd.org' '" References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.6i cc: Dan Nelson cc: "''freebsd-questions@freebsd.org' '" Subject: Re: Using int 13 while BSD is running X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Mar 2004 17:24:04 -0000 On Wed, Mar 10, 2004 at 08:49:17AM -0800, Jason Dictos wrote: > > > > To Jason: take care not to *write* anything to the disk via int 13h. > > I still don't think I understand why you are using FreeBSD for this > specific purpose. Why if you just >spend time escaping from the OS? > > We actually _like_ protected mode, it allows us to be more flexible and our > code doesn't have to be bastardized with 16 dos compilers ;). However in dos > we have garanteed hard drive support via int13 (Well almost garanteed, but > if an os can boot of the computer, we can access the disk), and I'm looking > for the same sorta garantee in BSD. People will be using this with raid > controllers, scsi hard disks, and ide drives (Server recovery), so there > will be many times when the hardware running the hd requires specific > support, which BSD may or may not have, point is we dont' want to manage > that. > > Make sense? Just because you can boot from the disk does not mean that the BIOS can read the whole disk. As an example I have an old computer running FreeBSD with a 1GB disk. The BIOS in this computer cannot handle disks larger than 512MB (which was a quite common limitation in older BIOSs). I can however boot from this disk since all the files needed for booting reside below the 512MB mark. Once I have booted FreeBSD I can access the whole disk precisely because FreeBSD does *not* use the BIOS, but use its own routines. -- Erik Trulsson ertr1013@student.uu.se