Path: utzoo!attcan!uunet!cs.utexas.edu!loyola!ross!doug
From: doug@ross.UUCP (doug carmean)
Newsgroups: comp.arch
Subject: MMUs and operating systems (was Re: Critera ...)
Message-ID: <232@ross.UUCP>
Date: 24 May 89 15:37:31 GMT
References: <3390@orca.WV.TEK.COM> <19088@winchester.mips.com> <230.ross.UUCP>
Reply-To: doug@ross.UUCP (doug carmean)
Organization: ROSS Technology, Austin, TX
Lines: 16


In <3390@orca.WV.TEK.COM> Andrew Klossner write (in response to my posting)
>An MMU is not a "device," to be "driven" easily by a single module.
>Big MMU differences cause ripples throughout the kernel, and in extreme
>cases can affect user code.

Notice that my posting stated that a "well written operating system requires
a change to a single driver...".  By well written I was referring 
specifically to SunOS, which requires very minor modifications to be ported
to a new MMU.  All of the code specific to the MMU is localized in
a single routine, not scattered throughout the kernel.  A new MMU will
not affect user code even in the extreme cases.
-- 
-doug carmean                           ross!doug@cs.utexas.edu
-ROSS Technology, 7748 Hwy 290 West Suite 400, Austin, TX 78736
-Don't let my sarcasm fool you: I have no sense of humor.