Path: utzoo!utgpu!watmath!att!cbnewsd!tainter
From: tainter@cbnewsd.ATT.COM (johnathan.tainter)
Newsgroups: comp.sys.atari.st
Subject: Re: Re^2: Multitasking on the ST
Message-ID: <1470@cbnewsd.ATT.COM>
Date: 30 Aug 89 21:28:50 GMT
References: <441@nixpbe.UUCP>
Reply-To: tainter@cbnewsd.ATT.COM (johnathan.tainter,ih,)
Organization: AT&T Bell Laboratories
Lines: 42

In article <441@nixpbe.UUCP> mboen@nixpbe.UUCP (Martin Boening) writes:
>And I use Gnu CC, which laughs in your face
>when you try to restrict it to 64K.

Gnu CC laughs in your face if you do anything of size on a machine less
than 2MEG. :-(

>And of course
>there's no paging (I don't know if you could implement paging as a pure
>software solution).

Sure you can.  You just have to implement an interpreter for the processor
so you can predict which instructions will fault when you run them.
The MC68000 can't handle page faults (no instruction restart or
instruction continuation).  Of course, this will slow it down a bit.

Now if had a MC68010 then we would have a possibility, but that would have
cost Atari another buck or two per unit and would have taken some rewriting
of the code which they weren't competent to do at the time, nor did they have
enough time to rewrite and get it out before the Amiga which Tramiel had just
failed to snarf.  Look at the system they did issue (shudder), which got
two years of "not invented here" responses before they admitted they were
going to fix some of the serious fatal bugs.

>Naturally MINIX is intended MOSTLY for learning, BUT I wouldn't call it a
>toy. There are lot's of developments to improve it's performance.

Don't fork and do significant volume of work without doing an exec though.
That will cost you big time.

>Martin

>PS: Maybe IDRIS will be shown at the Duesseldorf Atari Fair. Then I'll get
>a chance to look at it. I think it's a UNIX clone that actually is supposed
>to be used as a working OS.

From my experience with Idris on another machine I say this:  If given the
choice of working on Idris or having your throat slit and salt rubbed in
wound, take the latter!

--johnathan.a.tainter--
   att!ihlpb!tainter