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Date: Thu, 20 Apr 2006 22:40:33 -0400
Message-Id: <200604210240.k3L2eXhV010134@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: djgpp AT delorie DOT com
In-reply-to: <e29djr$nhd$1@emma.aioe.org> (do_not_have@sorry.bitbuck.cmm)
Subject: Re: dos buffer
References: <A8adnbpWz9FuPdjZnZ2dnUVZ_sednZ2d AT comcast DOT com> <e26mf1$ruh$1 AT emma DOT aioe DOT org> <20060420034145 DOT K3950 AT dynamite DOT narpes DOT com> <e29djr$nhd$1 AT emma DOT aioe DOT org>
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For DJGPP's purposes, consider these definitions wrt how they're
translated:

virtual -> segment table -> linear -> page table -> physical -> RAM chips

A virtual address may or may not represent a linear address (it won't,
for example, if the selector has an invalid value, or if the segment
table has a special entry in it, or if the address is beyond the end
of the segment.

A linear address may or may not represent a physical address depending
on whether or not the page table has a "present" entry for that page.
Non-present pages may be stored on disk.

A physical address may or may not map to physical RAM chips, depending
on how much memory you have ;-)