From owner-freebsd-stable Fri Jul 20 18:29:34 2001 Delivered-To: freebsd-stable@freebsd.org Received: from mass.dis.org (cust-P5-R6-162.POOL.ESR.SJO.wwc.com [206.112.109.162]) by hub.freebsd.org (Postfix) with ESMTP id 4D6C437B401 for ; Fri, 20 Jul 2001 18:29:26 -0700 (PDT) (envelope-from msmith@mass.dis.org) Received: from mass.dis.org (localhost [127.0.0.1]) by mass.dis.org (8.11.4/8.11.3) with ESMTP id f6L1SQd02267; Fri, 20 Jul 2001 18:28:27 -0700 (PDT) (envelope-from msmith@mass.dis.org) Message-Id: <200107210128.f6L1SQd02267@mass.dis.org> X-Mailer: exmh version 2.1.1 10/15/1999 To: janb@cs.utep.edu Cc: "Daniel C. Sobral" , Stefan Molnar , Marek Gorka , freebsd-stable@FreeBSD.ORG Subject: Re: FreeBSD 4.3 and 6G RAM In-reply-to: Your message of "Fri, 20 Jul 2001 19:22:17 MDT." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 20 Jul 2001 18:28:26 -0700 From: Mike Smith Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > Even, when there is not more than 4BG RAM? Should a facility such as this > not be disabled when not in use? It's not trivial to "disable", unfortunately. The core of the problem is that the 36-bit physical addresses have to be stored in 64-bit variables, which are *much* slower than the 32-bit variables we currently use. You can't adjust this at runtime, it has to be a compile-time option. There are other complications as well, which all add up to making this a serious amount of work to deal with, and more to the point, one that nobody has actually undertaken yet. -- ... every activity meets with opposition, everyone who acts has his rivals and unfortunately opponents also. But not because people want to be opponents, rather because the tasks and relationships force people to take different points of view. [Dr. Fritz Todt] V I C T O R Y N O T V E N G E A N C E To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message