From owner-freebsd-questions Mon May 15 15:49:42 2000 Delivered-To: freebsd-questions@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 60ED237B8D8 for ; Mon, 15 May 2000 15:49:38 -0700 (PDT) (envelope-from dg@implode.root.com) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id PAA10446; Mon, 15 May 2000 15:43:08 -0700 (PDT) Message-Id: <200005152243.PAA10446@implode.root.com> To: "Erin" Cc: "'Brian'" , "'Freebsd Questions'" Subject: Re: Max Physical Memory In-reply-to: Your message of "Mon, 15 May 2000 15:37:08 PDT." <004301bfbebe$1acefe20$8914820a@EndUser.sdccd.cc.ca.us> From: David Greenman Reply-To: dg@root.com Date: Mon, 15 May 2000 15:43:08 -0700 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >> The maximum that FreeBSD supports now and in the medium >> term future on the >> x86 platform is 4GB. Going beyond that requires majors >> changes to device drives and the VM system. > >Does the 32bit architecture partially responsible for the >4GB limit? If not, when do you forcast the changes to hit >the FreeBSD OS? Yes, the system was written to assume 32bit physical address space. The page table format changes when using the extended addressing and device drives have to be rewritten to do 64bit PCI address cycles. Some of the device driver changes are in the works (I recall Justin talking about extended address bits in the ahc driver, for example), but the VM system changes are probably a ways off and may never happen since the 64bit Itanium will eventually replace x86 on the high end, thus reducing the need to scale that far with x86. -DG David Greenman Co-founder, The FreeBSD Project - http://www.freebsd.org Creator of high-performance Internet servers - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message