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Date: Fri, 25 Apr 1997 05:18:34 -0500 (CDT)
From: Wayne Baety <mrfoine@enteract.com>
Reply-To: Wayne Baety <mrfoine@enteract.com>
To: David Langford <langfod@dihelix.com>
cc: Michael Smith <msmith@atrad.adelaide.edu.au>, joe@via.net,
        mrcpu@cdsnet.net, hackers@freebsd.org
Subject: Re: Can't put 512MB ram in box ... Extended memory question.
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On Tue, 22 Apr 1997, David Langford wrote:

> >> Why the need for the MAXMEM config variable?

Why not two MAXMEM variables...
MAXMEMLO MAXMEMHIGH or something the like

> >> 
> >> Why not just probe for maximum memosry size at boot time?
> >
> >Because there's no standard behaviour when it comes to accessing
> >nonexistent memory.  Some systems mirror their memory, ie. with 64M on
> >the board, addresses are all modulo-64M.  Others will spontaneously
> >reboot if you try to access an address with no memory behind them.