From owner-freebsd-hackers Mon Dec 16 15:14:56 1996 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id PAA12728 for hackers-outgoing; Mon, 16 Dec 1996 15:14:56 -0800 (PST) Received: from alpo.whistle.com (alpo.whistle.com [207.76.204.38]) by freefall.freebsd.org (8.8.4/8.8.4) with ESMTP id PAA12720 for ; Mon, 16 Dec 1996 15:14:41 -0800 (PST) Received: from current1.whistle.com (current1.whistle.com [207.76.205.22]) by alpo.whistle.com (8.8.2/8.8.2) with SMTP id PAA06478; Mon, 16 Dec 1996 15:02:42 -0800 (PST) Message-ID: <32B5D4E4.167EB0E7@whistle.com> Date: Mon, 16 Dec 1996 15:01:56 -0800 From: Julian Elischer Organization: Whistle Communications X-Mailer: Mozilla 3.0Gold (X11; I; FreeBSD 2.2-CURRENT i386) MIME-Version: 1.0 To: Terry Lambert CC: Joao Carlos Mendes Luis , tony@dell.com, eivind@dimaga.com, hackers@freebsd.org Subject: Re: Boot loader hacks was: Re: MAXMEM References: <199612162101.OAA02010@phaeton.artisoft.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Terry Lambert wrote: > > > Just a stupid question: Why does the boot loader should know if > > there's more than 64M or not on the system ? > > So it can tell the kernel. > > > Why couldn't it simply detect 64M at most, and let the kernel > > find the rest by itself ? Anyway, is what's done with the > > MAXMEM option, isn't it ? > > No; the kernel assumes what you tell it is true. If you use the > MAXMEM option, you are eternally stuck with that memory for that > particular kernel. Take it to a machine with more memory, and > you don't use the extra; take it to a machine with less, and you > are screwed. > I added code to OSF1/x86 to look for more ram and add it to the ammount reported by the bios.. it wasn't that hard!! the problem is that it needs to be done very early so that an access to non-existant memory doesn't produce an NMI when read from (on parity systems) or other similar problems.. julian