Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!snorkelwacker!apple!oracle!news
From: pnakada@oracle.com (Paul Nakada)
Newsgroups: comp.sys.apple2
Subject: Re: System programming for the Apple II (preferably the IIe)
Message-ID: <PNAKADA.90Mar6012126@pnakada.oracle.com>
Date: 6 Mar 90 09:26:04 GMT
References: <6673@hydra.gatech.EDU> <7368@latcs1.oz.au>
Sender: news@oracle.com
Organization: Oracle Corporation, Belmont, CA
Lines: 44
In-reply-to: stephens@latcs1.oz.au's message of 6 Mar 90 05:18:44 GMT

In article <7368@latcs1.oz.au> stephens@latcs1.oz.au (Philip J Stephens) writes:

[ stuff deleted ]

> Nice thought, but pretty much inpractical.
>    First of all, remember that Unix is multitasking, whereas the Apple IIe is
> not!  You'd have to modify the C sources quite drastically to get a single
> user version capable of running on an Apple.  Either that, or get your hands
> on one that isn't multitasking.
>    The same problems exist for implementing the virtual memory system, paging
> faults, disk I/O handling etc.  Basically, what I'm trying to get at is you
> can't port over a standard version of Unix from a Pyramid, Mips or Vax.
>    Someone has already mentioned the security aspects as well, which relates
> back to what ought to happen when a program crashes.  Unix expects to regain
> control in situations like this, but on an Apple that is not always possible!
> Put simply, the 6502 (and the Apple in general) couldn't cope with anything
> but a diluted version of Unix; and in that case, you'd be better off re-writing
> the C sources yourself!
>     Actually, writing a single user version of Unix from "scratch" wouldn't be
> that bad; if you're into that sort of thing...I would think that a basic
> version wouldn't be any more complex than DOS or ProDOS.  I wouldn't mind
> attempting it if I had the time ;-)


Philip, 
   your previous message contains many misconceptions that I would
like to clear up.

a) UNIX is a multiprocessing operating system (multitasking, whatever)

b) There is no such animal as a single process (which I imagine you refer
   to as single user) UNIX operating system.  UNIX is inherently multi
   processing, and thus multi user.

c) The Apple //e is a computer.  It is not an operating system.
   Therefore it should not be compared to an operating system.

d) In any case, the Apple //e was not designed with a multi processing
   operating system in mind, but this does not rule out the
   implementation of one despite obvious obstacles (of which you point
   out many)
 
-Paul Nakada
pnakada@oracle.com