From owner-freebsd-hackers Mon Nov 3 11:47:52 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id LAA27959 for hackers-outgoing; Mon, 3 Nov 1997 11:47:52 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from smtp04.primenet.com (smtp04.primenet.com [206.165.5.85]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id LAA27950 for ; Mon, 3 Nov 1997 11:47:48 -0800 (PST) (envelope-from tlambert@usr09.primenet.com) Received: (from daemon@localhost) by smtp04.primenet.com (8.8.7/8.8.7) id MAA22243; Mon, 3 Nov 1997 12:47:37 -0700 (MST) Received: from usr09.primenet.com(206.165.6.209) via SMTP by smtp04.primenet.com, id smtpd022236; Mon Nov 3 12:47:36 1997 Received: (from tlambert@localhost) by usr09.primenet.com (8.8.5/8.8.5) id MAA22785; Mon, 3 Nov 1997 12:47:31 -0700 (MST) From: Terry Lambert Message-Id: <199711031947.MAA22785@usr09.primenet.com> Subject: Re: >64MB To: tony@dell.com (Tony Overfield) Date: Mon, 3 Nov 1997 19:47:31 +0000 (GMT) Cc: tlambert@primenet.com, jamil@trojanhorse.ml.org, hackers@FreeBSD.ORG In-Reply-To: <3.0.3.32.19971031232621.007008f8@bugs.us.dell.com> from "Tony Overfield" at Oct 31, 97 11:26:21 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > >It reports less because the BIOS lies. > > That's not right. I'd like to see your patches to make > the BIOS honest. > > FreeBSD simply makes the wrong BIOS call. The particular > BIOS call made by the boot loader is limited to 16 bits > worth of Kilobytes. That's what I said: the BIOS lies. > To make matters worse, the kernel > eventually ignores that answer in preference to the lower > 16 bits of the actual value stored in CMOS, which is never > better and often worse, as it truncates the most > significant bits. Only on machines that are anal about not indicating more than 16M even though the bits are there for 64M for conformance with some bogus, antiquated IBM AT hardware document. 8-|. The problem is that the BIOS call made in the boot code should not be in the boot code at all, not that we should increase the size of the boot code yet again by calling the "good" BIOS call (quoted because it exists only on newer hardware, not all hardware), and falling back to the ignored one if it's not there. The problem with increasing the boot code size "just a tiny bit" is that there is *truly* no room for it (the ELF capable boot blocks that can still boot an a.out kernel have about 12 bytes left). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.