Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!ncar!gatech!usenet.ins.cwru.edu!ncoast!allbery
From: allbery@NCoast.ORG (Brandon S. Allbery KB8JRR/AA)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: 8-bit death
Message-ID: <1991May10.005049.8355@NCoast.ORG>
Date: 10 May 91 00:50:49 GMT
References: <1991May3.043704.10066@kessner.denver.co.us> <1991May5.024025.19463@sugar.hackercorp.com> <1991May7.064810.905@kessner.denver.co.us>
Reply-To: allbery@ncoast.ORG (Brandon S. Allbery KB8JRR/AA)
Followup-To: comp.sys.amiga.advocacy
Organization: North Coast Public Access Un*x (ncoast)
Lines: 59

As quoted from <1991May7.064810.905@kessner.denver.co.us> by david@kessner.denver.co.us (David Kessner):
+---------------
| In article <1991May5.024025.19463@sugar.hackercorp.com> peter@sugar.hackercorp.com (Peter da Silva) writes:
| >	"monitor" ROM resident, usually loads programs from tape. Provides
| >		the services of simple I/O, execution control.
+---------------

BIOS.

+---------------
| >	"program loader" loaded from disk (usually), provides a file system,
| >		program loading, execution control, simple I/O.
+---------------

What MS-DOS actually achieves.

+---------------
| >	"operating system" adds real device drivers and device independence,
| >		memory and CPU time management.
+---------------

What MS-DOS aspired to be, but was too inefficient and underfeatured to
achieve.  What CP/M-86 achieved.

+---------------
| >	"protected O/S" adds resource tracking and protection.
+---------------

What CCP/M-86 aspired to be, and partially succeeded at.

+---------------
| >DOS doesn't even qualify as an O/S to me. Neither does Mac OS, or any PC
| >system software prior to the Amiga.
+---------------

Peter, I fail to understand this.  Where does MacOS fall short?  Or are you
confusing the "OS" level with the "protected OS" or "multiuser OS" level?  If
it has to be pre-emptively multitasking before it can really be called an OS,
you neglected to indicate this in your definitions --- and serious OS
designers would disagree with you.

In reality, "multitasking OS" is a step between "protected OS" and "multiuser
OS", where things are protected just enough to deal with inter-process
contention but not with inter-user contention.  Then there's "multiprocessor
OS", which extends protection to the level of concurrent processes.

Except that you can have multitasking without protection (any multitasker on
an 8088/80286), multiuser without user access protection (MP/M) or even true
resource protection (MP/M-80!).  And special-purpose applications can have a
system with multitasking and advanced services but no program loading, thus
missing the "OS" level while incorporating features beyond it.  Another
example of meaningless artificial divisions....

++Brandon
-- 
Me: Brandon S. Allbery			  Ham: KB8JRR/AA  10m,6m,2m,220,440,1.2
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