From owner-freebsd-hardware@FreeBSD.ORG Sun Feb 1 11:05:53 2004 Return-Path: Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3B21A16A4CE for ; Sun, 1 Feb 2004 11:05:53 -0800 (PST) Received: from adsl-63-198-35-122.dsl.snfc21.pacbell.net (adsl-63-198-35-122.dsl.snfc21.pacbell.net [63.198.35.122]) by mx1.FreeBSD.org (Postfix) with ESMTP id 253BA43D53 for ; Sun, 1 Feb 2004 11:05:42 -0800 (PST) (envelope-from j_guojun@lbl.gov) Received: from lbl.gov (localhost.pacbell.net [127.0.0.1]) ESMTP id i11J6Kk6000394; Sun, 1 Feb 2004 11:06:21 -0800 (PST) (envelope-from j_guojun@lbl.gov) Sender: jin@adsl-63-198-35-122.dsl.snfc21.pacbell.net Message-ID: <401D4E2C.805C33AB@lbl.gov> Date: Sun, 01 Feb 2004 11:06:20 -0800 From: "Jin Guojun [NCS]" X-Mailer: Mozilla 4.76 [en] (X11; U; FreeBSD 4.9-RELEASE i386) X-Accept-Language: zh, zh-CN, en-US, en MIME-Version: 1.0 To: Michal Pasternak References: <20040131232022.GA20827@pasternak.w.lub.pl> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: Yuri Grebenkin cc: freebsd-hardware@freebsd.org Subject: Re: About CD-RW X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 Feb 2004 19:05:53 -0000 Michal Pasternak wrote: > > And another little question. What is better to have both CD-RW and HDD on > > one ata0 (master and slave) or HDD on ata0 and CD-RW on ata1? What gives > > best performance? I think that best one is when they are on different, > > bacause it become possible to only read via one and only write via other > > while copying data. Is it that way? > > Many people told me, that it is the best to have them on separate channels, > if this is possible. This really depends on IDE controllers. Most IDE controllers do not provide two separated IDE channels. They only have one internal IDE channel to fan out four connectors. Testing shows that two IDE drives on two buses can affect each other. So, it does not really matter where you connect to. In this case, using two buses may reduce the secondary bus arbitration, and gives a little bit better throughput. A few IDE controllers are real two channels, for example AMD MPX chipset. Some one told that nVidia PCI chipset is similar to MPX. Under this circumstance, using two buses will make difference on performance. -Jin