From owner-freebsd-hackers Thu Nov 6 16:54:27 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id QAA26144 for hackers-outgoing; Thu, 6 Nov 1997 16:54:27 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from usr01.primenet.com (tlambert@usr01.primenet.com [206.165.6.201]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id QAA26118 for ; Thu, 6 Nov 1997 16:54:19 -0800 (PST) (envelope-from tlambert@usr01.primenet.com) Received: (from tlambert@localhost) by usr01.primenet.com (8.8.5/8.8.5) id RAA19368; Thu, 6 Nov 1997 17:52:29 -0700 (MST) From: Terry Lambert Message-Id: <199711070052.RAA19368@usr01.primenet.com> Subject: Re: >64MB To: tony@dell.com (Tony Overfield) Date: Fri, 7 Nov 1997 00:52:27 +0000 (GMT) Cc: gurney_j@resnet.uoregon.edu, chuckr@glue.umd.edu, mike@smith.net.au, tlambert@primenet.com, jamil@trojanhorse.ml.org, hackers@FreeBSD.ORG, j_mini@efn.org In-Reply-To: <3.0.3.32.19971106150448.006d5438@bugs.us.dell.com> from "Tony Overfield" at Nov 6, 97 03:04:48 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > My ambiguous question reworded would say... > > Once you are in the kernel startup code and running in protected mode, > why not simply switch back to real mode for BIOS calls and etc. instead > of trying to set up a VM86() facility? I think it's easier and much > better for compatibility while booting. I don't understand how it's a compatability win. Plus there's still the issue of "what INT 13 disk maps to what controller and target", that's the reason we can't know the BIOS geometry to make up good fdisk data in the first place... Plus we need a VM86() in general in any case, since we may need to call the BIOS mode setting code for standard PCI/EISA/ISA video cards that are plugged into non-Intel hardware, etc., because card vendors don't know how to write data dependencies in a seperate area of their BIOS so a non-Intel OS could figure out how to program the card without needing information obtained under non-disclosure. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.