Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!brutus.cs.uiuc.edu!psuvax1!psuvm!cxt105
From: CXT105@PSUVM.BITNET (Christopher Tate)
Newsgroups: comp.sys.mac.hardware
Subject: Re: PMMU question
Message-ID: <89298.144700CXT105@PSUVM.BITNET>
Date: 25 Oct 89 18:47:00 GMT
References: <27044.2543231E@cmhgate.FIDONET.ORG> <35885@apple.Apple.COM>
 <1989Oct24.220445.707@eng.umd.edu>
Organization: Penn State University
Lines: 16

In article <1989Oct24.220445.707@eng.umd.edu>, russotto@eng.umd.edu (Matthew T.
Russotto) says:

> [...] And in one Apple document I found a reference in the index to WOM--
>Write-Only Memory, where you put information but you can never ever get
>it out.  It contained an X-Ref to a book by Bruce Tognazzi [...]

This is certainly quite possible.  If the memory addresses in question map
directly to chip registers, then you may well not be able to read from them.
An example of this was the old Commodore 64's (and possibly 128's) sound
chip management registers.  Reading the registers gave meaningless results.

-------
Christopher Tate                   | somewhere i have never travelled,
cxt105@psuvm.psu.edu               | gladly beyond any experience,
 ..!psuvax1!psuvm.bitnet!cxt105    | your eyes have their silence.