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Date:      Sun, 27 Apr 2003 08:04:35 +1000 (EST)
From:      Andy Farkas <andyf@speednet.com.au>
To:        Ruslan Ermilov <ru@freebsd.org>
Cc:        current@freebsd.org
Subject:   Re: i386/loader compiled with NOFORTH
Message-ID:  <20030427075835.Q42886-100000@hewey.af.speednet.com.au>
In-Reply-To: <20030426204542.GD66677@sunbay.com>

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On Sat, 26 Apr 2003, Ruslan Ermilov wrote:
> On Fri, Apr 25, 2003 at 02:46:26PM -0700, Terry Lambert wrote:
> > John Baldwin wrote:
> > > >
> > > > John, is there a way to fix btx/loader/whatever so that
> > > > heap memory is not limited to 640K?
> > >
> > > Not really.  At least, not easily.  We load the kernel up above 1mb,
> > > but we don't know how much memory lives up above 1mb and we assume
> > > that there is enough for the kernel and that's it.
> >
> > You are limited to what you can access in real mode, without
> > Gate A20 (16M, at which point the address space wraps).
> >
> Shhh, don't tell this anyone!  ;-)
>
> A20 (21th address line) allows one to access up to ffff:ffff
> byte, that is (1M + 64K - 16) bytes of memory.

Actually, you can access the entire 4GB of memory in "unreal" mode.

<http://x86.ddj.com/ddj/aug98/aug98.htm>;

--

 :{ andyf@speednet.com.au

        Andy Farkas
    System Administrator
   Speednet Communications
 http://www.speednet.com.au/





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