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Path: utzoo!mnetor!uunet!seismo!mcvax!botter!vuecho!michael
From: michael@psy.vu.nl (Michael Felt)
Newsgroups: comp.os.minix
Subject: Re: MAC and Minix
Message-ID: <17@vuecho.psy.vu.nl>
Date: Fri, 17-Jul-87 09:36:54 EDT
Article-I.D.: vuecho.17
Posted: Fri Jul 17 09:36:54 1987
Date-Received: Sat, 18-Jul-87 13:40:50 EDT
References: <1756@pbhye.UUCP> <990@vaxb.calgary.UUCP>
Reply-To: michael@psy.vu.nl (Michael Felt)
Organization: VU Psychologie, Amsterdam
Lines: 36
Keywords: C port ACK

In article <990@vaxb.calgary.UUCP> radford@calgary.UUCP (Radford Neal) writes:
>
>> Has anyone thought of porting Minix to the Mac or is that to wierd? ...
>
>
>I think it would be nifty to port MINIX to the Mac as a desk accessory.

Nice idea

>
>The main problem would be the C compiler for MINIX, which would have to 
>generate code that offsets all memory references from an address register.

I have written a couple 'back-ends' for the Amsterdam Compiler Kit (ACK)
with various memory models.
1. No seperate I/D 32K limit (all AboveA5).
2. Seperate I/D 32K limit text (aboveA5) 32K limit data (BelowA5)
3. Seperate I/D 'no limit text above A5', 32 K limit BelowA5 - data
4. NonSeperate I/D text & data aboveA5 ' no limit '
5. Seperate I/D, "classic model", jumptable aboveA5, global data belowA5

The flexibility in memory models is an attribute of EM (Encoding Machine),
the intermediate language of ACK.

I can give tips, but I can't send sources. Sorry.
Sources are not mine to send.

>If you did this right, however, you could be secure against wild MINIX 
>processes.
>
I have my reservations. Without memory protection a bad pointer
from any program can blow another program away.

Michael Felt
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