From owner-freebsd-hackers  Fri Oct 29 15:12: 2 1999
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To: Dan Nelson <dnelson@emsphone.com>
Cc: Lars Gerhard Kuehl <kuehl@lgk.de>,
	Mike Smith <mike@smith.net.au>, hackers@FreeBSD.ORG,
	Chuck Youse <cyouse@paradox.nexuslabs.com>
Subject: Re: Limitations in FreeBSD 
In-reply-to: Your message of "Fri, 29 Oct 1999 09:56:29 EST."
             <19991029095629.D48778@dan.emsphone.com> 
Date: Sat, 30 Oct 1999 08:11:12 +1000
From: Patryk Zadarnowski <patrykz@mycenae.ilion.eu.org>
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> In the last episode (Oct 29), Lars Gerhard Kuehl said:
> > > Think about it for a second.  How big is a pointer?
> > 
> > The Intel architecture still supports segmented memory,
> > so the effective maximum pointer size is 48 bit.

The extra 16 bits of the segment don't actually contribute to the
address space size on IA32, as Intel decided to do segment translation before
virtual address translation (ie, all segments have to fit in the same
32bit vaddr space). PPC, on the other hand.... ;) If you want a trully
gigantic address space, try a 64 bit PPC, it's got 80 bit addresses, even
if they're totally and utterly useless unless you're writing a SASOS.

Pat.


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