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From: pjc@r1.uucp (Peter Crowther (CAG ra))
Newsgroups: comp.object,comp.lang.c++
Subject: Re: Designing an object-oriented operating system in C++
Message-ID: <683@m1.cs.man.ac.uk>
Date: 16 Feb 90 10:22:54 GMT
References: <1187@bimacs.BITNET> <90037.103431UH2@PSUVM.BITNET>
Sender: news@cs.man.ac.uk
Reply-To: pjc@r1.UUCP (Peter Crowther (CAG ra))
Organization: University of Manchester, UK
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> There are some operating systems, eg, Minix, AmigaDos, and Mach, that
> employ a metaphor of separate processes passing messages back and forth
> to one another.  This sounds to me similar to a part of the OOP metaphor.

> Two questions --- is it easier or harder to create such an OS using an
> OOPL, and is it easier or harder to create an OOPL under such an operating
> system?

This is something of a side note... look at some papers on ACTORS. These are
(conceptually) concurrent processes, where each actor is a process. An Actor
has a Mailbox with a known mail address, and a set of Acquaintances (other
Actors whose mail addresses are known). An Actor also has a current Script;
note the use of 'current' as the Script can change. The basic processing cycle
for each Actor (and do remember that all run asynchronously) is:

	Wait until at least one message is in my Mailbox,
	Process that message using my current Script.
	(Repeat until blue in the face)

Note that an Actor can change its Script at any time. From what I can remember,
the old Script then runs through to completion on the current message and the
Actor can also start processing the next message with the new Script.


I haven't got any references handy; I know that someone in our University has
done some work on Actors but haven't got his mail address to hand. If you are
interested in this work, mail me. I'll either post or mail references and
e-mail addresses, depending on interest.

[Trevor, if you're reading this, I sure hope I've got the description right!]

		- Peter

Peter Crowther, Dept. of Electrical Engineering, University of Manchester,
		Manchester M13 9PL, England.
Internet: pcrowther@r1.cs.man.ac.uk	Janet: pcrowther@uk.ac.man.cs.r1
USENET:   mcvax!ukc!man.cs!pcrowther	Fishing net: Device for catching fish