Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!rutgers!ames!amdahl!drivax!alexande
From: alexande@drivax.UUCP
Newsgroups: comp.os.minix
Subject: Re: Memory handling in MINIX ?
Message-ID: <914@drivax.UUCP>
Date: Mon, 9-Feb-87 19:29:27 EST
Article-I.D.: drivax.914
Posted: Mon Feb  9 19:29:27 1987
Date-Received: Thu, 12-Feb-87 18:43:57 EST
References: <5490004@nucsrl.UUCP> <254@hqda-ai.UUCP> <7599@utzoo.UUCP> <4292@columbia.UUCP>
Reply-To: alexande@drivax.UUCP (Mark Alexander)
Organization: Kludges 'R' Us, Inc.
Lines: 23

In article <4292@columbia.UUCP> ji@garfield.columbia.edu.UUCP (John Ioannidis) writes:
>.EXE programs are patched at load time by the EXEC call so that they can
>be loaded anywhere in memory. There is no hardware support for it.

Yes, but .COM programs are not patched.  They run anywhere you load them
(if written properly).  As the DOS Technical Reference says about
program loading:

	For .COM programs:  all four segment registers contain the
	segment address of the initial allocation block...

Thus the segment registers can be thought of as a very cheap MMU.

This sort of scheme can be used on MINIX, but wouldn't allow shared code
(because code == data == stack == heap).

>Reading the manuals helps, you know...

Sure does!
-- 
Mark Alexander	...{hplabs,ucbvax!decvax}!decwrl!pyramid!amdahl!drivax!alexande
"This then is my story.  I have reread it.  It has bits of marrow
sticking to it, and blood, and beautiful bright-green flies."  --Nabokov