From owner-freebsd-hackers Sat Mar 23 15:20:25 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id PAA18562 for hackers-outgoing; Sat, 23 Mar 1996 15:20:25 -0800 (PST) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id PAA18556 for ; Sat, 23 Mar 1996 15:20:22 -0800 (PST) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id QAA08450; Sat, 23 Mar 1996 16:12:55 -0700 From: Terry Lambert Message-Id: <199603232312.QAA08450@phaeton.artisoft.com> Subject: Re: Adding a damn 2nd disk To: dave@kachina.jetcafe.org (Dave Hayes) Date: Sat, 23 Mar 1996 16:12:55 -0700 (MST) Cc: j@uriah.heep.sax.de, freebsd-hackers@FreeBSD.ORG In-Reply-To: <199603231944.LAA12669@kachina.jetcafe.org> from "Dave Hayes" at Mar 23, 96 11:44:39 am X-Mailer: ELM [version 2.4 PL24] 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 > >Andreas was wrong here. Fdisk needs the geometry the BIOS is using -- > >not the geometry the disk claims to be. (The latter is largely > >irrelevant, that's why it's hidden by default. Anyways, it cannot be > >expressed in plain C/H/S for any modern disk.) > > Given the nature of the dissention about what this geometry really > means, isn't there a sufficiently powerful abstraction one can use > to represent the information that fdisk and disklabel need...one > that covers all drives? > > If you have that, writing any user inferface is MUCH easier. Windows 95 converts from BIOS to protected mode drivers during the boot process (to the point of causing conversion of open file handles for TSR's loaded in real mode to carry over). Conceptually, it requires alot of BIOS information to be accumulated by the boot code for use in identifying the protected mode devices BIOS equivalent drive assignments (which are not documented or stored anywhere -- they are an artifact of PSOT). You have the choice of implementing a real mode boot (/boot has been proposed) and moving the change to protected mode out of the second stage boot and into the boot program as the last thing before it starts executing kernel code... or implementing a virtual machine. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.