Path: utzoo!attcan!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!mcvax!kth!sunic!kullmar!pkmab!ske
From: ske@pkmab.se (Kristoffer Eriksson)
Newsgroups: comp.sys.amiga.tech
Subject: Re: MEMF_PHYSICAL?
Summary: How does the protection work?
Message-ID: <1251@pkmab.se>
Date: 8 Jun 89 18:25:20 GMT
References: <8906030123.AA14671@jade.berkeley.edu>
Reply-To: ske@pkmab.UUCP (Kristoffer Eriksson)
Organization: Peridot Konsult i Mellansverige AB, Oerebro, Sweden
Lines: 28

In article <8906030123.AA14671@jade.berkeley.edu> 451061@UOTTAWA.BITNET (Valentin Pepelea) writes:
>Valentin's AmigaOS 2.0:
>
>1. Single addressing space.
>2. Virtual memory.
>3. Memory protection.
    -----------------
>4. Resource tracking.

>His error is pretty easy to catch if you though out how virtual memory is to
>be implemented. You see, the virtual memory handler on a single address space
>OS does not care what program is running in what memory. It merely swaps in and
         -----------------------------------------------
>out individual pages one-by-one. Full programs never have to be swapped out
>entirely, just individual pages. This will become more obvious in a couple of
>weeks.  :-)

How can the OS and MMU provide any protection, if they don't care what program
is using what memory?

-- 
Kristoffer Eriksson, Peridot Konsult AB, Hagagatan 6, S-703 40 Oerebro, Sweden
Phone: +46 19-13 03 60  !  e-mail: ske@pkmab.se
Fax:   +46 19-11 51 03  !  or ...!{uunet,mcvax}!sunic.sunet.se!kullmar!pkmab!ske