From owner-freebsd-hackers Thu Mar 25 17:50:25 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from nomad.dataplex.net (nomad.dataplex.net [216.140.184.132]) by hub.freebsd.org (Postfix) with ESMTP id D4BDA14E95 for ; Thu, 25 Mar 1999 17:50:19 -0800 (PST) (envelope-from rkw@dataplex.net) Received: from localhost (rkw@localhost) by nomad.dataplex.net (8.9.2/8.9.2) with ESMTP id TAA01086; Thu, 25 Mar 1999 19:49:50 -0600 (CST) (envelope-from rkw@dataplex.net) X-Authentication-Warning: nomad.dataplex.net: rkw owned process doing -bs Date: Thu, 25 Mar 1999 19:49:50 -0600 (CST) From: Richard Wackerbarth Reply-To: rkw@dataplex.net To: Mike Smith Cc: hackers@freebsd.org Subject: Re: Booting from non-standard floppy In-Reply-To: <199903260033.QAA01323@dingo.cdrom.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thu, 25 Mar 1999, Mike Smith wrote: > > I needed to cram "a few more bytes" on a floppy. > > recall, the "bios" read the 0th sector (boot1) and jumped to it. > > That short piece of code got the disk format from the label and > > read in the next piece of the loader. After that, address->c.t.s > > was under the software control. > > > > Is there some reason we no longer do this? > > Several; > > - Disklabels on floppies can't be trusted. > - All disks are treated as equal, and geometries in disklabels on many > disks can't be trusted. Often you can't get to the disklabel until > after you've made assumptions about geometry anyway. > > You can save space a couple of ways; if you haven't already, gzip > everything except the loader. Been there. My stuff is based on the PicoBSD kernel. Almost all the extras are already purged. > If you don't need the loader for anything other than loading a kernel, > throw the loader away; the bootblocks themselves know how to load ELF > kernels. Thanks, that will save a little. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message