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From: peter@graffiti.UUCP (Peter da Silva)
Newsgroups: net.micro.68k
Subject: Re: Re: Re: Re: Info on OS9 Operating System
Message-ID: <314@graffiti.UUCP>
Date: Wed, 16-Oct-85 11:06:37 EDT
Article-I.D.: graffiti.314
Posted: Wed Oct 16 11:06:37 1985
Date-Received: Mon, 21-Oct-85 00:41:36 EDT
References: <347@wlbr.UUCP> <9500001@datacube.UUCP> <126@mcrware.UUCP> <275@graffiti.UUCP> <138@mcrware.UUCP>
Organization: The Power Elite, Houston, TX
Lines: 38

microware!kim:

	We don't need a bunch of flames. I was just trying to point out that
UNIX is perfectly viable on low-end systems. Don't assume I'm attacking your
baby. I'm not. All I'm doing is defending mine :->.

> That HP machine is a single-user machine.  The OS was an HP in-house
> clone of UNIX.  Not even in the same class as OS-9.

The O/S *is* UNIX: it's a very carefully enhanced port. The only reason the
machine is billed as single-user is that it is extremely low on disk space.
There is no reason you can't run a shell out a serial port & run two users.
It'll just be real frustrating...

> > 	2) True, but... I don't want to do serious work on a machine without
> > 	   an MMU any more. It's so frustrating... even sickening... to watch
> > 	   a lost pointer or bad copy of foocalc blow away everything & write
> > 	   garbage over a:\*.*
> > 
> The MMU does a little more than protect memory.  It allows manipulation of a
> process' logical address spaces.  In fact, the UNIX fork system call CANNOT
> operate without an MMU (or some type of segment/base register allocation
> scheme [ala 80*86]). 

If you are careful about the code your compiler generates there's no reason
you can't. That's all the UNIX-es for the PC do.

> > Sure can. Xenix, Venix, and PC/IX all run without an MMU, apparently quite
> > well. HPUX runs without a hard drive, and I'd use it if the Integral didn't
> > have a typical Hewlett-Packard price tag. Neither seem to be necessary for
> > UNIX.
> Sorry.  Those machines use Intel processors with their segment register
> on-chip MMUs.  In this case the MMU is free.

The Intel segment registers qualify for on-chip MMUs about as well as I qualify
as a race-car driver. If you generate properly position-independant code, which
should be possible for the 68000 or the 6809, there's no reason you can't port
UNIX to it.