Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdahl!drivax!alexande
From: alexande@drivax.UUCP (Mark Alexander)
Newsgroups: comp.os.misc
Subject: Re: a very naive Question???
Message-ID: <3880@drivax.UUCP>
Date: 14 Oct 88 21:44:07 GMT
References: <835@amethyst.ma.arizona.edu> <5085@medusa.cs.purdue.edu>
Reply-To: alexande@drivax.UUCP (Mark Alexander)
Organization: Bob-ist Temple of Monterey
Lines: 24

In article <5085@medusa.cs.purdue.edu> spaf@cs.purdue.edu (Gene Spafford) writes:
>The definition I use in teaching OS courses is the following:
>If the address presented to the system may be bound to a physical
>address different from that seen by the program, you have
>virtual memory.

You seem to be saying that if you're using the address translation
hardware of the computer (like the LDT and GDT in protected mode of
the <gag, barf> 286), you've got virtual memory.

This may be a fine definition for school, but out here in the real
world, where we have to deal with nasty stuff like marketing & sales,
it wouldn't work.

We sell an operating system that uses the protection and address
translation features of the 286, 386, V60, and 68010/68451 hardware,
but if we tried to tell potential customers "our operating system does
virtual memory!", we'd be laughed at, or accused of false advertising.
When we get around to implementing swapping or demand paging
(depending on the processor), then and only then will we be able to
make that claim.
-- 
Mark Alexander	(UUCP: amdahl!drivax!alexande)
"Bob-ism: the Faith that changes to meet YOUR needs." --Bob (as heard on PHC)