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Path: utzoo!watmath!clyde!rutgers!uwvax!astroatc!prairie!dan
From: dan@prairie.UUCP
Newsgroups: comp.os.minix
Subject: Re: Memory handling in MINIX ?
Message-ID: <405@prairie.UUCP>
Date: Sun, 25-Jan-87 13:01:23 EST
Article-I.D.: prairie.405
Posted: Sun Jan 25 13:01:23 1987
Date-Received: Mon, 26-Jan-87 01:47:13 EST
References: <5490004@nucsrl.UUCP> <254@hqda-ai.UUCP>
Reply-To: dan@prairie.UUCP (Daniel M. Frank)
Organization: Prairie Computing, Madison, Wisconsin
Lines: 20

In article <254@hqda-ai.UUCP> merlin@hqda-ai.UUCP (David S. Hayes) writes:
>In article <5490004@nucsrl.UUCP>, naim@nucsrl.UUCP (Naim Abdullah) writes:
>> Is a MMU a standard part of a pc ?
>
>     No.  One of the major failings of the PC architecture.  On
>the AT (80286), there is some help here, but not much.  

   What does "some help here" mean?  The 286 has virtual, relocatable
segments, memory protection, protection rings, segment permissions, 
separate global and local segment spaces, and call gates.  All the
386 adds is paging of the underlying linear address space.  Admittedly,
that's a big "all", but the substantial stuff is all in the 286.  All
the real Unices for the AT provide virtual memory a la the pre-paging
Vax implementations.

-- 
      Dan Frank
	ARPA: dan@db.wisc.edu			ATT: (608) 255-0002 (home)
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