From owner-freebsd-arch@FreeBSD.ORG Tue Aug 24 17:01:35 2010 Return-Path: Delivered-To: freebsd-arch@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id F20C4106566C for ; Tue, 24 Aug 2010 17:01:35 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from harmony.bsdimp.com (bsdimp.com [199.45.160.85]) by mx1.freebsd.org (Postfix) with ESMTP id AF7BB8FC08 for ; Tue, 24 Aug 2010 17:01:35 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by harmony.bsdimp.com (8.14.3/8.14.1) with ESMTP id o7OGtasY067234; Tue, 24 Aug 2010 10:55:36 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Tue, 24 Aug 2010 10:55:46 -0600 (MDT) Message-Id: <20100824.105546.1002438156525560711.imp@bsdimp.com> To: xcllnt@mac.com From: "M. Warner Losh" In-Reply-To: References: <760A97A4-62D2-4900-915D-CA5D889855E1@mac.com> <20100824155205.C2A535B23@mail.bitblocks.com> X-Mailer: Mew version 6.3 on Emacs 22.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: freebsd-arch@FreeBSD.org Subject: Re: RFC: enhancing the root mount logic X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Aug 2010 17:01:36 -0000 In message: Marcel Moolenaar writes: : : On Aug 24, 2010, at 8:52 AM, Bakul Shah wrote: : >> : >> I see your point and buy into the argument, but not : >> entirely. I explicitly mentioned "embedding" and so : >> far your arguments include things like GENERIC being : >> 10MB or Linux server startup. : >> : >> We're not exactly discussing the same thing are we? : > : > This friend's company used linux in an embedded system [it : > was a fileserver product. Presumably the OS had to run in a : > restricted environment since the FS space would be for their : > customers' use + you don't want to have to reload the OS when : > a disk dies! And yet you want the ability to upgrade your OS : > s/w etc.] : > : > In my job[-2] we used FreeBSD as an embedded OS. IIRC we just : > ran from a readonly flash FS as root. An upgrade was just a : > new FS image, including kernel + utilities. Didn't Juniper : > do something similar? : : Juniper's approach is still heavily rooted in PC-class H/W. : With Book-E, ARM and MIPS products for the low(er)-end and : in particular without these products having a real harddisk, : the existing way has shown it's problems and limitations. : : Also: Juniper has hacked a few tools, including the kernel : at large and md(4) in particular to implement features they : needed/wanted, which I'd like to get away from. You can get away from a large MD by having a small MD and pivoting to large storage. Linux does this, as Bakul said, and it scales from the ultra-small 4MB Mips router up to the highest multicore server. Warner