Path: utzoo!attcan!uunet!lll-winken!ames!pacbell!hoptoad!peora!rtmvax!bilver!wbeebe
From: wbeebe@bilver.UUCP (bill beebe)
Newsgroups: comp.os.minix
Subject: Re: PC Minix/64KB limit
Message-ID: <419@bilver.UUCP>
Date: 19 Feb 89 03:01:54 GMT
References: <8752@louie.udel.EDU> <2047@ast.cs.vu.nl>
Reply-To: wbeebe@bilver.UUCP (bill beebe)
Organization: W. J. Vermillion, Winter Park, FL
Lines: 22

In article <2047@ast.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:

>The problem is the brain-damaged 8088/80286 CPU.  You can only access
>64K segments without doing terrible things, like making all pointers 32 bits.
>This is slow, bulky, and generally unpleasant.  The whole MM has been designed
>to work with a single linear address space.  The 68000 has this.  The PC
>only has it if you restrict yourself to 64K I & D space.  Going to a segmented
>model requires a major change to MM, which I don't want to do.  Someday,
>when the normal low-end PC has a 386 in it, I can envision changing MINIX
>to use 1 32-bit segment.

Oh, *please* don't call the 8088/80286 brain-damaged! :-). It's been very,
very good to me. Your 80386 low-end PC is closer than you think. Intel
has dropped the 80386SX price to $89 in single quantities, and $50 in
quantity 1000. This makes it directly competitive to the 16 MHz 80286.

For your information I have decided to *investigate* porting Minix
to the 80376 (no real mode, no paging). The 80376 comes up in protected
mode, and I want a rom-based 32-bit version with real-time extensions.
*If* I decide to tackle this (I have a hardware design in Schema II+ ),
I'll email you with the ugly details. I'll be using Intel's C386 and
ASM386 with the builder-binder (I have to anyway).