From owner-freebsd-hackers Tue Jun 3 18:38:06 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id SAA08497 for hackers-outgoing; Tue, 3 Jun 1997 18:38:06 -0700 (PDT) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id SAA08489 for ; Tue, 3 Jun 1997 18:38:01 -0700 (PDT) Received: (from msmith@localhost) by genesis.atrad.adelaide.edu.au (8.8.5/8.7.3) id LAA09807; Wed, 4 Jun 1997 11:07:39 +0930 (CST) From: Michael Smith Message-Id: <199706040137.LAA09807@genesis.atrad.adelaide.edu.au> Subject: Re: DMA for IDE drives ? In-Reply-To: <199706031502.JAA04331@pluto.plutotech.com> from "Justin T. Gibbs" at "Jun 3, 97 09:58:58 am" To: gibbs@plutotech.com (Justin T. Gibbs) Date: Wed, 4 Jun 1997 11:07:38 +0930 (CST) Cc: luigi@labinfo.iet.unipi.it, toor@dyson.iquest.net, hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Justin T. Gibbs stands accused of saying: > Do the newer IDE drives support any concept similar to tagged queueing? > Perhaps via EATA? Supporting DMA is only half the battle in my mind as you > won't get anywhere near the throughput of a SCSI drive if you can't > schedule and have the drive reorder multiple transactions at a time. Not AFAIK; the drive has to remain selected for the entire duration of the transaction. I can't easily see how you could support disconnection and multiple transactions within the scope of the wd interface. > Justin T. Gibbs -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[