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From: csc@watmath.UUCP (Jan Gray)
Newsgroups: net.micro.atari16,net.micro.amiga,net.micro.68k
Subject: Re: 68000 Memory Managment
Message-ID: <3077@watmath.UUCP>
Date: Wed, 10-Sep-86 18:14:44 EDT
Article-I.D.: watmath.3077
Posted: Wed Sep 10 18:14:44 1986
Date-Received: Thu, 11-Sep-86 07:34:22 EDT
References: <508@elmgate.UUCP> <64@mit-prep.ARPA> <510@elmgate.UUCP> <6985@sun.uucp> <823@navajo.STANFORD.EDU> <79@mtxinu.UUCP>
Reply-To: csc@watmath.UUCP (Jan Gray)
Organization: U of Waterloo, Ontario
Lines: 25
Xref: mnetor net.micro.atari16:1885 net.micro.amiga:4611 net.micro.68k:1204

In article <79@mtxinu.UUCP> ed@mtxinu.UUCP (Ed Gould) writes:
>>> I hate to tell you folks, but Andy Bechtolsheim here at Sun has a patent 
>>> (applied for and granted) on using the untranslated addresses as the 
>>> RAS addresses and doing the MMU address translation before the column 
>>> addresses are needed for CAS.
>>
>>How the hell can the patent office grant patents like this?  It's sort
>>of like patenting the idea of grounding DTACK on a 68000 or putting
>>chocolate ice cream in root beer; the idea is too obvious.  To coin a
>>phrase, it's patently ridiculous.
>
>If it's so obvious, why didn't anyone think of it before Andy did?

I did; it's the obvious way of building an MMU that doesn't introduce extra
wait states, and applies to the 68K family because the other common
16/32 bit CPUs don't require custom MMUs.

>Is the Set-UID bit (also patented) any less obvious?  Not to me,
>now that I've seen them both.  But I never thought of them; neither
>did anyone else, evidently, before their respective inventors.

Like the guy who patented the xor cursor, or Apple's pull-down menu
patent, I'll believe it when it holds up in court.

Jan Gray   Northern Software and University of Waterloo   885-5921