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From: mash@mips.UUCP (John Mashey)
Newsgroups: comp.arch
Subject: Re: Horizontal pipelining [really: multi-tasking is alive and well]
Message-ID: <1062@winchester.UUCP>
Date: Sun, 6-Dec-87 20:06:06 EST
Article-I.D.: winchest.1062
Posted: Sun Dec  6 20:06:06 1987
Date-Received: Sat, 12-Dec-87 06:13:46 EST
References: <201@PT.CS.CMU.EDU> <388@sdcjove.CAM.UNISYS.COM>
Reply-To: mash@winchester.UUCP (John Mashey)
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 49

In article <2326@killer.UUCP> elg@killer.UUCP (Eric Green) writes:
>In article <1006@winchester.UUCP> mash@winchester.UUCP (John Mashey) writes:
>>In article <2581@mmintl.UUCP> franka@mmintl.UUCP (Frank Adams) writes:
>>>Another trend which might doom the idea is that towards individual
>>>(single-user) computers.  The future of multi-tasking on such machines is
>>>very much in question; if it becomes a big thing, there is no problem.

(me):
>>Hopefully, multi-tasking will some year come to single-user computers :-)

>Actually, multi-tasking single-user computers have been available for years.
>OS-9 on the TRS-80 Color Computer, for example, and AmigaDOS on the Commodore
>Amiga. Just because the IBM PEE-CEE and Apple Macintosh don't have a
>multitasking oprating system, doesn't mean that the rest of the world is stuck
>with single tasking (and note that both IBM and Apple intend to introduce
>multitasking OS's Real Soon Now).

>I think that we'll see the demise of ancient CP/M-derived operating systems
>Real Soon Now (as Marketing would say :-).

My comment was intended to display humor and amazement that there could be
doubt about the future of multi-tasking, especially in this newsgroup.
It is clear that the posting was not crisp enough, as I got numerous pieces
of mail urging me to look at AmigaDOS and others to assure myself that
multi-tasking was indeed possible on a single-user computer.

Given that PCs were hardly the first single-user computers,
and that multi-tasking on single-user systems has existed almost as long as
the systems have, I'd guess that the current prevalence of
single-tasking systems is just an anomoly of the cost/performance &
feature (i.e. lack of builtin memory-mapping) combinations of late 70s /
early 80s microprocessors.
For many years, each successive generation of
computers (mainframes, minis, micros) seemed to repeat most of the mistakes
of the earlier ones.  Now that current micros have:
	a) useful addressability (32-bits)
	b) on-chip MMUs (hence no cost-cutting reason to omit them)
	c) reasonable design for use with high-level languages
	d) more-or-less reasonable design for use with multi-tasking OSs
and given that DRAMs are getting big enough that it's almost HARD to build
tiny-memory systems, the original reasons for this aberration are rapidly
going away, leaving only the software legacy [unfortunately].

Anyway, sorry for the lack of clarity in my original comment.
-- 
-john mashey	DISCLAIMER: 
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