From owner-freebsd-arch Sun Oct 13 12: 0:48 2002 Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3B35037B401 for ; Sun, 13 Oct 2002 12:00:47 -0700 (PDT) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id D986E43E7B for ; Sun, 13 Oct 2002 12:00:46 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.5/8.12.4) with ESMTP id g9DJ0ZPQ054778; Sun, 13 Oct 2002 12:00:35 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.5/8.12.4/Submit) id g9DJ0ZAM054777; Sun, 13 Oct 2002 12:00:35 -0700 (PDT) (envelope-from dillon) Date: Sun, 13 Oct 2002 12:00:35 -0700 (PDT) From: Matthew Dillon Message-Id: <200210131900.g9DJ0ZAM054777@apollo.backplane.com> To: "M. Warner Losh" Cc: tlambert2@mindspring.com, ticso@cicely.de, hch@infradead.org, wes@softweyr.com, vova@sw.ru, nate@root.org, arch@FreeBSD.org Subject: Re: Database indexes and ram References: <3DA954CF.98B0891A@mindspring.com> <20021013.060851.113437955.imp@bsdimp.com> <3DA9B4A8.194A02FC@mindspring.com> <20021013.120847.31902907.imp@bsdimp.com> Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Google is your friend. I found a quick reference on the PCI bus. A 32 bit PCI bus can support 64 bit addresses through the use of two address cycles prefacing the data transfer. That said, we all know how shoddy a large chunk of the PCI market is (well, really the *entire* PC market, not just PCI). Just because the spec allows it doesn't mean the chipset/motherboards support it or, more importantly, support it reliably. Remember all the cache/MMU bugs that showed up in the 486 series when people started actually using the MMU? IMHO as much as I like the coolness of throwing more then 4G into a PC not really designed to take more then 4G, I personally believe that it is wiser to distribute processing at that point rather then spend money on more specialized (and finicky) configurations. You will see me throw more then 4G into a box when the next generation capable of dealing with more then 4G becomes commoditized. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message