Date: Tue, 12 Jun 2001 09:27:30 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Mike Smith <msmith@FreeBSD.ORG> Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>, freebsd-hackers@FreeBSD.ORG Subject: Re: Patented algorithm in FreeBSD Message-ID: <30671.992330850@critter> In-Reply-To: Your message of "Mon, 11 Jun 2001 15:47:47 PDT." <200106112247.f5BMllP03936@mass.dis.org>
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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
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