From owner-freebsd-amd64@FreeBSD.ORG Fri Dec 31 22:13:49 2004 Return-Path: Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 82CBA16A4CE for ; Fri, 31 Dec 2004 22:13:49 +0000 (GMT) Received: from dragon.nuxi.com (trang.nuxi.com [66.93.134.19]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5472243D41 for ; Fri, 31 Dec 2004 22:13:49 +0000 (GMT) (envelope-from obrien@NUXI.com) Received: from dragon.nuxi.com (obrien@localhost [127.0.0.1]) by dragon.nuxi.com (8.13.1/8.13.1) with ESMTP id iBVMDmXT015656; Fri, 31 Dec 2004 14:13:48 -0800 (PST) (envelope-from obrien@dragon.nuxi.com) Received: (from obrien@localhost) by dragon.nuxi.com (8.13.1/8.13.1/Submit) id iBVMDlQ2015655; Fri, 31 Dec 2004 14:13:47 -0800 (PST) (envelope-from obrien) Date: Fri, 31 Dec 2004 14:13:47 -0800 From: "David O'Brien" To: Michael Reifenberger Message-ID: <20041231221347.GA1467@dragon.nuxi.com> References: <20041230090557.I82461@fw.reifenberger.com> <20041231221342.E90486@fw.reifenberger.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041231221342.E90486@fw.reifenberger.com> User-Agent: Mutt/1.4.1i X-Operating-System: FreeBSD 6.0-CURRENT Organization: The NUXI BSD Group X-Pgp-Rsa-Fingerprint: B7 4D 3E E9 11 39 5F A3 90 76 5D 69 58 D9 98 7A X-Pgp-Rsa-Keyid: 1024/34F9F9D5 cc: freebsd-amd64@FreeBSD.org Subject: Re: Migrating i386 to amd64 X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: freebsd-amd64@FreeBSD.org List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 31 Dec 2004 22:13:49 -0000 On Fri, Dec 31, 2004 at 10:17:17PM +0100, Michael Reifenberger wrote: > On Fri, 31 Dec 2004, Ade Lovett wrote: > ... > >>Do my old i386 ports (like X etc) work under amd64? > > > >Simple answer. No. Steps (1) and (2) above are implying a complete > >binary system reinstall. Part of the data you should probably be backing > >up is a list of installed packages so you can put the amd64 ones back in > >after installing kernel+userland. > > > > Autsch. > Thats what I didn't want to hear. > Thanks anyway! > > BTW: Do I have any benefit of using this hardware (2GB RAM) with amd64 > in favour of i386 (besides a bigger virtual address space)? Yes. A 64-bit kernel is often more efficient because so many of the kernel data structures these days are 64-bit counters, etc.. Also the AMD64 ABI has 8 more general purpose registers, which gives the compiler a lot more to work with in optimizing and allows parameters to be passed thru registers vs. the slower memory stack. I also would not dismiss the benefits of the larger virtual address space. There are applications where the kernel really benefits from not being constrained to its limited amount of VA in 32-bit mode. -- -- David (obrien@FreeBSD.org)