Subject: Re: NetBSD 1.6.1 not finding all memory
To: Jaromir Dolecek <>
From: D'Arcy J.M. Cain <>
List: tech-kern
Date: 12/24/2003 07:37:11
On December 20, 2003 03:26 am, Jaromir Dolecek wrote:
> D'Arcy J.M. Cain wrote:
> > I installed 8GB into an i386 system and rant 1.6.1 on it.  The dmesg
> > looks like this:
> AFAIK NetBSD doesn't support the PSE36 extension, so it would only
> use up to 4GB physical RAM.

I have been trying to find information about PSE36 and what I have found is a 
little sketchy.  However, it appears that PSE36 is a hack for systems that 
use 32 bit pointers.  Don't we use 64 bit addressing?  Shouldn't we be seeing 
all of this memory without turning it into a RAMDrive or something?

Is it possible that there is simply a counter somewhere that is making a 
limiting assumption about memory?  I have seen that before where a simple 
change to a line of code allowed us to go from 16 bit UIDs to 32 bit UIDs.  
There was no real limitation in the structures.  It was just that the code 
made an artificial restriction in a bounds check.

I am going to start looking for this type of thing but if anyone has a 
definitive answer I would appreciate it.

D'Arcy J.M. Cain <>