Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!asuvax!ncar!noao!arizona!gerhard
From: gerhard@cs.arizona.edu (Gerhard Mehldau)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Crippled ROM in LC
Summary: Say what?
Message-ID: <2773@optima.cs.arizona.edu>
Date: 5 May 91 23:11:12 GMT
References: <91122.124005SYSMEST@GECRDVM1.BITNET> <1991May5.183049.16243@mcs.drexel.edu>
Distribution: usa
Organization: U of Arizona CS Dept, Tucson
Lines: 23

In article <1991May5.183049.16243@mcs.drexel.edu>, upsiu@mcs.drexel.edu (Paul Siu) writes:

> [...]

> 1) No support for PMMU, and math co, so it can't run virtual memory.  Since it
>    doesn't support virtual memory, Apple decided that 32-bit clean ROMs was
>    unnecessary, so third party products are still limited to 14MB.

Huh?  It is my understanding that the LC contains the same ROMs as the
IIsi, IIci, and IIfx, which are 32-bit clean.  The 14MB limit is a result
only of the missing PMMU; consequently, if you put a 68030 or 68040 board
(with the built-in PMMU) in the '020 PDS slot, you will be able to address
more than 14MB of memory.

> [...]

- Gerhard

-- 
-> Gerhard Mehldau
   Dept. of Computer Science	internet: gerhard@cs.arizona.edu
   University of Arizona	uucp:     {cmcl2,noao,uunet}!arizona!gerhard
   Tucson, AZ 85721, U.S.A.	voice:    +1 (602) 621-4632