From owner-freebsd-hackers Tue Jun 12 0:27:58 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by hub.freebsd.org (Postfix) with ESMTP id 40FF137B405; Tue, 12 Jun 2001 00:27:40 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter (localhost [127.0.0.1]) by critter.freebsd.dk (8.11.3/8.11.3) with ESMTP id f5C7RUr30673; Tue, 12 Jun 2001 09:27:30 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Mike Smith Cc: Mikulas Patocka , freebsd-hackers@FreeBSD.ORG Subject: Re: Patented algorithm in FreeBSD In-Reply-To: Your message of "Mon, 11 Jun 2001 15:47:47 PDT." <200106112247.f5BMllP03936@mass.dis.org> Date: Tue, 12 Jun 2001 09:27:30 +0200 Message-ID: <30671.992330850@critter> From: Poul-Henning Kamp Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In message <200106112247.f5BMllP03936@mass.dis.org>, Mike Smith writes: >> Hi >> >> Go to http://www.uspto.gov/patft/, search for patent number 5873127, and >> you will find the description of mapping page table entries into virtual >> memory via one page directory entry pointing to the page directory itself >> - exactly what FreeBSD does with PTDPTDI and APTDPTDI entries on i386. >> (including using alternate space as in get_ptbase() in i386/pmap.c to >> access page table entries of different processes). > >It'd be hard to build a case on this patent, though; since it was granted >in 1996, and the technique is as old as the hills, proving prior art >would probably be relatively straightforward. Well, the application date is what counts, and that's mar1992, but I'm pretty sure that Bill Jolitz had them beat to that date already... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message