From owner-freebsd-hackers Mon Mar 17 22:24:56 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id WAA06883 for hackers-outgoing; Mon, 17 Mar 1997 22:24:56 -0800 (PST) Received: from who.cdrom.com (who.cdrom.com [204.216.27.3]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id WAA06853 for ; Mon, 17 Mar 1997 22:24:51 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by who.cdrom.com (8.8.5/8.6.11) with ESMTP id VAA27240 for ; Mon, 17 Mar 1997 21:55:25 -0800 (PST) Received: (from msmith@localhost) by genesis.atrad.adelaide.edu.au (8.8.5/8.7.3) id QAA15812; Tue, 18 Mar 1997 16:24:59 +1030 (CST) From: Michael Smith Message-Id: <199703180554.QAA15812@genesis.atrad.adelaide.edu.au> Subject: Bootstrapping (was Re: wd driver questions) In-Reply-To: <199703180543.VAA13412@lestat.nas.nasa.gov> from Jason Thorpe at "Mar 17, 97 09:43:21 pm" To: thorpej@nas.nasa.gov Date: Tue, 18 Mar 1997 16:24:58 +1030 (CST) Cc: msmith@atrad.adelaide.edu.au, hackers@freebsd.org X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Jason Thorpe stands accused of saying: > > Thing wot uses simplistic file services to assemble from data on > > disk (kernel link instructions, object files) a kernel and runs it. > > ...oh... I rather like just having A Kernel Image and loading it :-) That's nice in it's own way, but it falls short on a few things, like being able to page bits of the kernel, replace bits of it on the fly, load and discard drivers etc. > Basically, you're talking about two-stage there... but the only reason > to use two-stage is space constraints (stupid limit on PCs, space until > file system begins on SPARCs, etc.) Yup. > If you don't hardcode the block numbers of the secondary boot program > into the primary, you have to include all the file system reading code, > which sort of defeats "small". Well, the current FreeBSD bootloader manages that in 7.5K along with a reasonably healthy amount of cruft. > installboot(8) deals with all of it anyhow, and since you currently > have to run something to stash the primary bootstrap into the right > sector, it's not that big of a deal :-) It just grates that you're putting something into the filesystem and then duplicating that information somewhere else. If I throw a new boot program in /boot, I don't necessarily want to have to hardcode its location into the stage-1 bootstrap. Or for that matter what if I want to choose between several different boot programs? -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[