Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!amdcad!ames!ll-xn!mit-eddie!uw-beaver!cornell!oravax!clay
From: clay@oravax.UUCP (McFarland)
Newsgroups: comp.misc
Subject: Re: Message based OSs (was "Re: GNU Manifesto")
Message-ID: <198@oravax.UUCP>
Date: 15 Feb 88 17:08:41 GMT
References: <1447@sugar.UUCP> <227@gandalf.littlei.UUCP>
Organization: Odyssey Research Associates, Ithaca, New York
Lines: 41


In article <227@gandalf.littlei.UUCP> adams@littlei.UUCP (Robert Adams) writes:
>From article <1447@sugar.UUCP>, by peter@sugar.UUCP (Peter da Silva):
>> MINIX isn't terribly real. It's realler than GNU (after all, it's out :->),
>> but it's got a small fraction of V7, and it's buggy. Comes from having
>> everything handled by messages.
>
>I would like an explanation of this.  It seems like it would be a
>wonderful computer architecture discussion because many systems are
>moving from procedural based interfaces to message based interfaces
>and, if that tends to create code that's inherently buggy, we certainly
>have a problem on our hands.
>
>Have any comments on this, Peter?  Anyone else?
>
>	-- Robert Adams
>	...!littlei!adams

Theoretically, message-based architectures are inherently less buggy
than procedure-call architectures; one reason is that control-flow 
bugs are confined to the entity which receives a message. However,
you must really design a message-based system. If you produce a 
message-based system by holding a procedure-call system in your
hands, facing in the direction of Alan Kay, and whispering "message"
(thus magically changing "calls" to "sends") what you have is a kludge.
The kludge will contain all previous bugs + bugs in the message handler
+ bugs resulting from unexpected interactions between the message
structure and the existing procedure structure.

You get the same problems if you try to put a classical mainframe
architecture on a chip :-).
 


Clay Brooke-McFarland		    Odyssey Research Associates

--------------------------------------------------------------|
"We didn't expect much, and we got most of what we expected." |
							      |
				- Tom Steel		      |
--------------------------------------------------------------|