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From: "Rashid Karimov." <rashid@haven.ios.com>
Message-Id: <199507102054.QAA01985@haven.ios.com>
Subject: Re: 2.0.5 64 meg RAM limit?
To: a00776@giant.mindlink.net (Toomas Losin)
Date: Mon, 10 Jul 1995 16:54:10 -0400 (EDT)
Cc: freebsd-questions@freebsd.org
In-Reply-To: <m0sVOxU-0001pEC@giant.mindlink.net> from "Toomas Losin" at Jul 10, 95 12:57:35 pm
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> 
		Hi there,

> I've got an interesting situation with our news server, running 2.0.5R.  It's
> just been expanded from 64 megs to 128 but the OS doesn't recognize the upper
> 64.  To the best of my knowledge the BIOS is setup correctly.

	There is a problem with certain BIOS'es - they report 
	wrong amount to memory to OSes. I've seen it with 
	few different brands of PCs. 
	There is also #define LAGRMEM , which you probably have
	to define to allow kernel to work with > 64M of RAM.

	What I usually do is :

	I've changed the macdep.c source code : substituted the BIOS 
	call which asks the PC about RAM installed via something
	like:

	biosextmem = 128000;

	and #define LARGEMEM in kernel config file.

	Works fine for me.

	If there is a limit on amount of RAM one can put into computer,
	it's certainly somewhere _above 128 Mb

> 
> Is there a default 64 meg limit?  Can I specify an option to tell the kernel
> how much memory there is?  I've been digging through the source but nothing
> obvious jumps out at me (other than hard coding the amount - something I don't
> really want to do).
> 

	And one can easily define its own define - so he/she'll be able
	to define the amount of memory to use thru config file - w/o
	hacking the kernel in such unpleasant way :)

	Should be pretty safe , since the kernel analizes the RAM from
	the bottom up and uses only thr RAM till first nonexisting/nonvalid
	page



	Rashid