From owner-freebsd-current Wed Aug 27 05:04:55 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id FAA28166 for current-outgoing; Wed, 27 Aug 1997 05:04:55 -0700 (PDT) Received: from hda.hda.com (hda-bicnet.bicnet.net [208.220.66.37]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id FAA28161 for ; Wed, 27 Aug 1997 05:04:49 -0700 (PDT) Received: (from dufault@localhost) by hda.hda.com (8.8.5/8.8.5) id HAA03779; Wed, 27 Aug 1997 07:17:26 -0400 (EDT) From: Peter Dufault Message-Id: <199708271117.HAA03779@hda.hda.com> Subject: Re: IDE vs SCSI was: flags 80ff works (like anybody doubted it) In-Reply-To: <19970826082726.17963@keltia.freenix.fr> from Ollivier Robert at "Aug 26, 97 08:27:26 am" To: roberto@keltia.freenix.fr (Ollivier Robert) Date: Wed, 27 Aug 1997 07:17:26 -0400 (EDT) Cc: current@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL25 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > Hmmm. If we're going to talk SCSI perf, let's get seriously SCSI here > > then: Quantum XP39100W drive on 2940UW controller: (...) > > 104857600 bytes transferred in 10.974902 secs (9554309 bytes/sec) > > Aren't you disappointed ? You're only a mere 2 MB/s faster with a Wide > connection... I'd expect it more in the 14 MB/s range, no ? Well designed fast buses (with well designed fast peripherals) give good bus utilization as the devices burst full speed on the bus. Put two of these disks on that bus and compare how the performance degrades versus two on the wide connection. The chances are that when you're buying this kind of disk you'll be buying another soon. Peter -- Peter Dufault (dufault@hda.com) Realtime development, Machine control, HD Associates, Inc. Safety critical systems, Agency approval