From owner-freebsd-questions Fri Oct 25 9:48:49 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4630237B401 for ; Fri, 25 Oct 2002 09:48:48 -0700 (PDT) Received: from q.closedsrc.org (ip233.gte15.rb1.bel.nwlink.com [209.20.244.233]) by mx1.FreeBSD.org (Postfix) with ESMTP id BD9D543E65 for ; Fri, 25 Oct 2002 09:48:47 -0700 (PDT) (envelope-from lplist@closedsrc.org) Received: by q.closedsrc.org (Postfix, from userid 1002) id 6E69D53E8; Fri, 25 Oct 2002 09:47:51 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by q.closedsrc.org (Postfix) with ESMTP id 6A31253DC; Fri, 25 Oct 2002 09:47:51 -0700 (PDT) Date: Fri, 25 Oct 2002 09:47:51 -0700 (PDT) From: Linh Pham To: Kevin Stevens Cc: "Jack L. Stone" , lewiz , Steve Warwick , Subject: Re: UDMA limited to 33 - resolution In-Reply-To: <20021023161917.H11289-100000@babelfish.pursued-with.net> Message-ID: <20021025094521.B58366-100000@q.closedsrc.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On 2002-10-23, Kevin Stevens scribbled: # However, it *is* correct that all devices on a UDMA channel must support # UDMA, so yes, the above is a problem. I don't recall if all devices must # also be the same UDMA speed (66/100/133) or not, bbelieve that is true # too. This is not a BSD issue, it is part of the UDMA spec. IIRC- The channel will run at the speed of the slowest device, meaning that if you have a drive that is capable of ATA/66 and a drive capable of ATA/33 on the same channel, then the channel will run at ATA/33. If you have a drive at ATA/100 and a drive that is only capable of PIO4, then the speed of the channel will be knocked down to either PIO4 or ATA/33 (the latter will only occur if the PIO4 drive is also capable to running at ATA/33, just without DMA). -- Linh Pham lplist@closedsrc.org Webmaster and FreeBSD Geek http://closedsrc.org closedsrc.org Every solution breeds new problems To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message