From owner-freebsd-hardware Mon Aug 24 15:49:32 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id PAA19750 for freebsd-hardware-outgoing; Mon, 24 Aug 1998 15:49:32 -0700 (PDT) (envelope-from owner-freebsd-hardware@FreeBSD.ORG) Received: from dingo.cdrom.com (ppp-db.dialup.hilink.com.au [203.2.144.21]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id PAA19740 for ; Mon, 24 Aug 1998 15:49:28 -0700 (PDT) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost [127.0.0.1]) by dingo.cdrom.com (8.9.1/8.8.8) with ESMTP id PAA00910; Mon, 24 Aug 1998 15:46:38 GMT (envelope-from mike@dingo.cdrom.com) Message-Id: <199808241546.PAA00910@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Graeme Tait cc: freebsd-hardware@FreeBSD.ORG, info@boatbooks.com Subject: Re: UDMA Support In-reply-to: Your message of "Mon, 24 Aug 1998 12:37:50 MST." <35E1C10E.1AA3@echidna.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 24 Aug 1998 15:46:36 +0000 From: Mike Smith Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > Mike Smith wrote: > > > > > Does FreeBSD have Ultra DMA support or will it have it? > > > > FreeBSD 3.0 supports IDE DMA. SCSI disks will give better performance > > in multiple-disk or high load scenarios. > > Assuming I'm running an Ultra ATA drive (IBM 7200 RPM 10GB or 14GB to be > specific) under 2.2.7, what benefits would the Ultra DMA support under > 3.0 bring, and under what conditions (read/write, file size etc.)? I/O transactions to/from the disk will consume (much) less CPU time. This is a win if you have more than one process active and not disk-bound (eg. a world build using -pipe, X server, etc.) Disk throughput is also higher on P6 and above because they do PIO poorly. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message