Path: utzoo!yunexus!geac!syntron!jtsv16!uunet!ncrlnk!ncr-sd!hp-sdd!ucsdhub!ucsd!rutgers!mailrus!bbn!rochester!kodak!bmt!tvf
From: tvf@bmt.UUCP (Thomas V. Frauenhofer)
Newsgroups: comp.os.misc
Subject: Re: a very naive Question???
Message-ID: <261@bmt.UUCP>
Date: 24 Oct 88 18:46:16 GMT
Article-I.D.: bmt.261
References: <835@amethyst.ma.arizona.edu> <5085@medusa.cs.purdue.edu> <664@cme-durer.ARPA>
Reply-To: tvf@bmt.UUCP (Thomas V. Frauenhofer)
Organization: Business Modeling Techniques, Inc., Rochester, NY
Lines: 42

In article <664@cme-durer.ARPA> wallace@cme-durer.ARPA (Evan Wallace) writes:
>In article <5085@medusa.cs.purdue.edu>, spaf@cs.purdue.edu (Gene Spafford) writes:
>> Virtual memory does not mean that the virtual address range is bigger
>> than the physical address range -- it could be smaller, as in
>
>In "An Introduction to Operating Systems" by Deitel virtual storage
>is defined to be a storage area larger than the primary storage
>area (memory).  This is in direct contradiction with G. Spafford's
>definition, but in complete agreement with common sense.  Also this
>definition is even in my webster's dictionary with a 1966 date of
>origin.?

In deference to what you say, consider the BBN Butterfly.  A 68000 can only
address 16 Meg tops.  Special hardware facilitates being able to address
memory on other processors, so your physical address space is > 16 Meg.
This is clearly an example where the virtual memory space is SMALLER than
the physical memory space (and I learned this in my operating systems course).

>
>> That's how I've taught it in OS courses at both Purdue and
>> Georgia Tech, and that's consistent with many OS texts....
>
>It's unfortunate that this kind of thing gets passed on to students
>who will then continue its propagation.

On the contrary, let's here it for professors who challenge their students to
be at the cutting edge (like mine).

One of my pet beefs with software engineers (of which I'm as guilty as anyone)
is that once we've figured out one way that something works, we close our
minds to other methods/techniques to be used or ways it could work.  "Intuitive"
reasoning is not always the best way to approach a topic.
-----
Tom Frauenhofer 	...!rutgers!rochester!kodak!bmt!tvf

BLOOM: You can't kill the actors!  They're human beings!
BIALYSTOCK: Oh yeah? You ever eat with one?
-- 
Tom Frauenhofer 	...!rutgers!rochester!kodak!bmt!tvf

BLOOM: You can't kill the actors!  They're human beings!
BIALYSTOCK: Oh yeah? You ever eat with one?