From owner-freebsd-questions@FreeBSD.ORG Thu Aug 30 22:04:01 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8411016A417 for ; Thu, 30 Aug 2007 22:04:01 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from ch-smtp01.sth.basefarm.net (ch-smtp01.sth.basefarm.net [80.76.149.212]) by mx1.freebsd.org (Postfix) with ESMTP id 10E1813C48E for ; Thu, 30 Aug 2007 22:04:00 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from c83-253-31-60.bredband.comhem.se ([83.253.31.60]:54782 helo=falcon.midgard.homeip.net) by ch-smtp01.sth.basefarm.net with esmtp (Exim 4.66) (envelope-from ) id 1IQs7M-0004ix-3T for freebsd-questions@freebsd.org; Fri, 31 Aug 2007 00:04:00 +0200 Received: (qmail 421 invoked from network); 31 Aug 2007 00:03:53 +0200 Received: from owl.midgard.homeip.net (10.1.5.7) by falcon.midgard.homeip.net with ESMTP; 31 Aug 2007 00:03:53 +0200 Received: (qmail 42775 invoked by uid 1001); 31 Aug 2007 00:03:53 +0200 Date: Fri, 31 Aug 2007 00:03:53 +0200 From: Erik Trulsson To: User Bobby Message-ID: <20070830220353.GA42640@owl.midgard.homeip.net> Mail-Followup-To: User Bobby , freebsd-questions@freebsd.org References: <20070830172127.M11085@susanne.tomatoseed.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070830172127.M11085@susanne.tomatoseed.org> User-Agent: Mutt/1.5.16 (2007-06-09) X-Originating-IP: 83.253.31.60 X-Scan-Result: No virus found in message 1IQs7M-0004ix-3T. X-Scan-Signature: ch-smtp01.sth.basefarm.net 1IQs7M-0004ix-3T 23eac8ef7cba939c7962957977fa94d2 Cc: freebsd-questions@freebsd.org Subject: Re: 4gb address space limitation for i386 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Aug 2007 22:04:01 -0000 On Thu, Aug 30, 2007 at 05:32:09PM -0400, User Bobby wrote: > I have an IBM xSeries 350 4xPIII with 5.5gb of RAM, and see that only about > 3.5gb is being used under the i386 port. I've been looking through the > archives to try and figure out what the root of the problem is and I amn't > quite sure I know which part of the situation is the real problem. > > Is it a limitation of the i386 port? That is to say, if there were a > specific PIII (i686?) port, would this problem be overcome? Or is it a > hardware limitation? It is a hardware limitation. > Is it necessary to use a not-clean method to access > the extra address space (is this what PAE is?) That is exactly what PAE is for. >, and there's no clean > way around it, regardless of the port? Correct. > > I was looking at building a PAE kernel, but was discouraged by the lack of > usb and certain SCSI support, both of which I'd really like to have (in the > case of SCSI, need to have). Is this lack of support because of an > inherent difficulty in the hardware, or could it be overcome in a stable > way with modification of the device driver code? All drivers could potentially be made to work correctly together with PAE. For some of them it would probably require substantial and non-trivial modifications to the driver code. > > My basic (and very hypothetical) question - if I had unlimited time and > knowledge (I have limited both), what direction would I take to get access > to all 5.5gb of RAM on this particular computer? Use a PAE-enabled kernel. Fix the drivers you need that do not currently work correctly with PAE (or persuade/bribe/blackmail/hire somebody else to fix the drivers.) -- Erik Trulsson ertr1013@student.uu.se