Path: utzoo!mnetor!uunet!husc6!bu-cs!madd
From: madd@bu-cs.BU.EDU (Jim Frost)
Newsgroups: comp.sys.ibm.pc
Subject: Re: PC AT clones, MSDOS and OS2 - request for info.
Message-ID: <22359@bu-cs.BU.EDU>
Date: 3 May 88 23:26:18 GMT
References: <23861@ucbvax.BERKELEY.EDU>
Reply-To: madd@bu-it.bu.edu (Jim Frost)
Followup-To: comp.sys.ibm.pc
Organization: Boston University Distributed Systems Group
Lines: 32

In article <23861@ucbvax.BERKELEY.EDU> brand@janus.UUCP (Graham Brand) writes:
|This brought up the more fundamental question of the difference between
|the 8086, 80286 and 80386. I had thought that the main difference was
|that the 80286 supported truw multitasking while the '386 supported that
|as well as true multiuser capability.

All of the processors can support multiuser and multitasking in the
IBM PC configuration (they support a clock interrupt that can give
time slicing).  The newer processors also contain memory management
and memory protection mechanisms which are vital when making a robust
operating system, but are not necessary.  (This is basically a
"necessary" versus "sufficient" argument.)  For proof of this, note
that ersions of UNIX are around for the 8086, 80286, and 80386.

The newer processors also run faster than the older, making them more
useful in a multitasking environment (more things get done faster, you
know).

As for multiuser and multitasking, ANY multitasking operating system
that supports multiple I/O devices (such as serial lines) can be made
to be multiuser.  Yes, this includes OS/2.  I'd be willing to place
money on companies coming out with multiuser versions of OS/2 within a
couple of years, providing OS/2 really catches on (and it looks like
it will).

Note that a multiuser operating system can be made without
multitasking.  An easy way to do this is to poll each terminal for a
function, do it, then continue polling.  Many database systems work
this way.

jim frost
madd@bu-it.bu.edu