Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 7 Feb 2001 21:11:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 7 Feb 2001 21:11:34 -0500 Received: from smtprelay.abs.adelphia.net ([64.8.20.11]:57835 "EHLO smtprelay3.abs.adelphia.net") by vger.kernel.org with ESMTP id ; Wed, 7 Feb 2001 21:11:22 -0500 Message-ID: <3A81FF41.316BF761@adelphia.net> Date: Wed, 07 Feb 2001 21:06:57 -0500 From: Stephen Wille Padnos X-Mailer: Mozilla 4.76C-SGI [en] (X11; U; IRIX64 6.5 IP28) X-Accept-Language: en MIME-Version: 1.0 To: "A.Sajjad Zaidi" CC: linux-kernel@vger.kernel.org Subject: Re: Promise, DMA and RAID5 problems running 2.4.1 In-Reply-To: <3A81FDAF.43DE0791@vgkk.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "A.Sajjad Zaidi" wrote: > > do you understand that you can't really have raid on ide involving > > two drives on the same channel? > > Is that just because of performance or are there other problems? Its working > fine as it is, but Im considering setting up all drives as masters (2x > ATA-100, 2x ATA-66). It's because IDE is a blocking bus - each drive must complete its' task before the data bus is released for the next IO operation. So, the first drive will finish writing to the disk before the second drive can start. (That's one reason why SCSI is preferred for high end systems - you can "disconnect" from an IO operation to allow other IO's to be sent to other devices on the same bus) -- Stephen Wille Padnos Programmer, Engineer, Problem Solver swpadnos@adelphia.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/