From owner-freebsd-hackers Mon Apr 1 21:12:32 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id VAA06949 for hackers-outgoing; Mon, 1 Apr 1996 21:12:32 -0800 (PST) Received: from who.cdrom.com (who.cdrom.com [204.216.27.3]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id VAA06943 for ; Mon, 1 Apr 1996 21:12:30 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by who.cdrom.com (8.6.12/8.6.11) with ESMTP id VAA27607 for ; Mon, 1 Apr 1996 21:12:12 -0800 Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id OAA11178; Tue, 2 Apr 1996 14:45:00 +0930 From: Michael Smith Message-Id: <199604020515.OAA11178@genesis.atrad.adelaide.edu.au> Subject: Re: HDD cpu usage (IDE vs. SCSI). To: koshy@india.hp.com (A JOSEPH KOSHY) Date: Tue, 2 Apr 1996 14:44:59 +0930 (CST) Cc: msmith@atrad.adelaide.edu.au, hackers@freebsd.org In-Reply-To: <199604020445.AA210060355@fakir.india.hp.com> from "A JOSEPH KOSHY" at Apr 2, 96 10:15:54 am 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 A JOSEPH KOSHY stands accused of saying: > ms> No, you're not understanding. For a given CPU, IDE will _always_ use more > ms> CPU time than SCSI. Period. > > I'm afraid I don't understand too; I recently had the oppurtunity to examine > a Future Domain TMC-1680 card. From what I could see this was an ISA card > with no bus-mastering capability. After the card had read in data from the > scsi bus, it would interrupt and the CPU had to use PIO to copy data from > the card to the system buffers. Pedant 8) I consider non-busmaster SCSI controllers to be at least as bad as IDE, if not worse. > The issue really is how much performance you are getting for your rupee. > The last time I checked here, a 1-disk SCSI sub-system cost around twice as > much as an equivalent IDE 1-disk sub-system. This doesn't hold for larger disk capacities. How much would you pay for a 7200rpm 4GB IDE disk? You're basically making the same point that I am - if performance is an issue, then SCSI is the animal of choice, cost permitting. > Koshy -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[