Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id <S130036AbRBQIRu>; Sat, 17 Feb 2001 03:17:50 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org
	id <S129545AbRBQIRk>; Sat, 17 Feb 2001 03:17:40 -0500
Received: from zooty.lancs.ac.uk ([148.88.16.231]:22264 "EHLO
	zooty.lancs.ac.uk") by vger.kernel.org with ESMTP
	id <S130036AbRBQIRa>; Sat, 17 Feb 2001 03:17:30 -0500
Message-Id: <l03130344b6b3e2eb2f9e@[192.168.239.101]>
In-Reply-To: <Pine.LNX.4.30.0102161828500.14561-100000@anime.net>
In-Reply-To: <4.3.2.7.2.20010216211931.00c6d360@mail.osagesoftware.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Date: Sat, 17 Feb 2001 08:16:51 +0000
To: Dan Hollis <goemon@anime.net>, David Relson <relson@osagesoftware.com>
From: Jonathan Morton <chromi@cyberspace.org>
Subject: re:  XOR  [ was: Linux stifles innovation... ]
Cc: <linux-kernel@vger.kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

>>  > > > You know XOR is patented (yes, the logical bit operation XOR).

>>  > > 	But wasn't that Xerox that had that?

>>  > US Patent #4,197,590 held by NuGraphics, Inc.

>> The patent was for using the technique of using XOR for dragging/moving
>> parts of a graphics image without erasing other parts.  Also, since the
>> patent was granted in 1980, the inventors have had their 17 years of patent
>> protection, and we're all free to use the technique - legally!
>
>So you approve of 4,197,590 and think it was an innovative and non obvious
>invention in 1980?

Dunno about that, but I have heard of "clever techniques" using XOR in
graphic sprite manipulation being used in microcomputer games in the
early/mid 80's.  No mention of NuGraphics' patent was present - in fact
this code was available in an "Assembly for fun" type book which I still
have a copy of.

The computer on which these techniques was demonstrated was the BBC
Microcomputer, released in 1981 and based on a 2 MHz 6502.  Similar
techniques were doubtless used on games for the Apple ][ which was released
several years previously using a 1 MHz 6502.

--------------------------------------------------------------
from:     Jonathan "Chromatix" Morton
mail:     chromi@cyberspace.org  (not for attachments)
big-mail: chromatix@penguinpowered.com
uni-mail: j.d.morton@lancaster.ac.uk

The key to knowledge is not to rely on people to teach you it.

Get VNC Server for Macintosh from http://www.chromatix.uklinux.net/vnc/

-----BEGIN GEEK CODE BLOCK-----
Version 3.12
GCS$/E/S dpu(!) s:- a20 C+++ UL++ P L+++ E W+ N- o? K? w--- O-- M++$ V? PS
PE- Y+ PGP++ t- 5- X- R !tv b++ DI+++ D G e+ h+ r- y+
-----END GEEK CODE BLOCK-----


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/