From owner-freebsd-stable Wed Jul 18 9:23:20 2001 Delivered-To: freebsd-stable@freebsd.org Received: from maila.telia.com (maila.telia.com [194.22.194.231]) by hub.freebsd.org (Postfix) with ESMTP id 614F037B403 for ; Wed, 18 Jul 2001 09:23:14 -0700 (PDT) (envelope-from ertr1013@student.uu.se) Received: from d1o913.telia.com (d1o913.telia.com [195.252.44.241]) by maila.telia.com (8.11.2/8.11.0) with ESMTP id f6IGNDq22039 for ; Wed, 18 Jul 2001 18:23:13 +0200 (CEST) Received: from ertr1013.student.uu.se (h185n2fls20o913.telia.com [212.181.163.185]) by d1o913.telia.com (8.8.8/8.8.8) with SMTP id SAA15152 for ; Wed, 18 Jul 2001 18:23:12 +0200 (CEST) Received: (qmail 91004 invoked by uid 1001); 18 Jul 2001 16:22:30 -0000 Date: Wed, 18 Jul 2001 18:22:29 +0200 From: Erik Trulsson To: freebsd-stable@FreeBSD.ORG Subject: Re: FreeBSD 4.3 and 6G RAM Message-ID: <20010718182229.A86118@student.uu.se> Mail-Followup-To: freebsd-stable@FreeBSD.ORG References: <20010718105637.A97286@student.uu.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.19i 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 On Wed, Jul 18, 2001 at 05:04:45PM +0100, Jonathan Belson wrote: > Hiya > > > > i have an intel 4400 platform equipped with 4 xeon processors and 6G ram. > > > the mainboard is based on the ServerWorks ServerSet II HE chipset (by > > > intel), which supports up to 16G RAM (or 32G, i'm not sure at the moment). > > > > > > i have installed FreeBSD 4.3-STABLE. > > > > > > unfortunately, the system seems unable to work with this amount of ram. > > > > FreeBSD does not support more than 4G RAM (at least not on x86, I > > don't know about Alpha). > > My suggestion would be to remove the extra 2G RAM from the machine and > > see if things work better then. (FreeBSD will not be able to use it > > anyway so you don't lose anything by removing it.) > > Dumb question: by my calculations, a 32bit address register can only > address 2**32 bytes of memory, ie. 4GB. Is it possible for your > average P3/Athlon to addres more than this? Does it use banking/ > MMU tricks? > Not a dumb question but yes, and yes. Modern x86 CPUs can address more than 4 GB of physical RAM. I think this was introduced with the Pentium Pro but I am not certain. Yes, it uses MMU tricks to do it. Note that even though the physical memory may be more than 4 GB the address space of a single process is still only 32 bits so a single process still cannot address more than 4 GB of RAM. -- Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message