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From: dillon@CORY.BERKELEY.EDU (Matt Dillon)
Newsgroups: net.micro.amiga
Subject: Re: Re: 68000 Memory Managment
Message-ID: <8609090131.AA23747@cory.Berkeley.EDU>
Date: Mon, 8-Sep-86 21:31:57 EDT
Article-I.D.: cory.8609090131.AA23747
Posted: Mon Sep  8 21:31:57 1986
Date-Received: Tue, 9-Sep-86 08:43:47 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: University of California at Berkeley
Lines: 17

>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.  Sooner or later, it's going to cost some
>competitors a WHOLE lot of money.

Wrong.  The idea is too universal for any lawsuit that would come about from
it to hold up in court... It's like patenting a FOR loop.  Additionaly, you
can easily get around the patent by passing ALL the address lines through to
the MMU, and spec'ing a faster time input->output for the LSB address lines.
There is no mention of dynamic anything in the MMU, and all a dynamic ram
board sees are half the address lines immediately available for processing,
and the other half not-yet available.  Physically, almost every MMU
these days pass the LSB N-bits (depending on the page side) anyway, but
simply latch them all at once on the output.

				-Matt