From owner-freebsd-questions Wed Sep 27 17:37:58 1995 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id RAA20362 for questions-outgoing; Wed, 27 Sep 1995 17:37:58 -0700 Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id RAA20347 for ; Wed, 27 Sep 1995 17:37:43 -0700 Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.9/8.6.9) id KAA21233; Thu, 28 Sep 1995 10:28:40 +0930 From: Michael Smith Message-Id: <199509280058.KAA21233@genesis.atrad.adelaide.edu.au> Subject: Re: PC configuration advice wanted. To: serges@umr.edu (Doug S.) Date: Thu, 28 Sep 1995 10:28:39 +0930 (CST) Cc: msmith@atrad.adelaide.edu.au, questions@freebsd.org In-Reply-To: from "Doug S." at Sep 27, 95 08:20:08 am Content-Type: text Content-Length: 1859 Sender: owner-questions@freebsd.org Precedence: bulk Doug S. stands accused of saying: > > > I'm very close to buying what Gateway here in the UK call a > > > a "P5-90 Premium Multimedia". This has: > > > > > > P90 Processor > > > 16MB EDO RAM > > > 1Gb EIDE disk > > > > DO NOT BUY IDE DISK! Especially with the rest of this config; IDE disk > > (and so little of it) would be a Really Bad Idea. > > Okay, so why is this such a "Really Bad Idea". Opinions aside. > Does FBSD have trouble with EIDE configurations? > > SCSI is nice, but its margin over EIDE isnt all that big. This is my > opinion, anyway. Ok, Mike's Canonical List of Why IDE Is Really Bad: 1) IDE interfaces use PIO, requiring CPU intervention for every byte transferred. All decent SCSI interfaces use busmaster DMA, which soak unused memory bandwidth, reducing the impact of disk I/O on compute performance. 2) IDE disks can't disconnect, or accept multiple commands, so you can only have one command at a time outstanding, and thus the drive can't sort outstanding commands to optimise actuator movement. SCSI does all this and lots more. 3) SCSI disks are transportable; when you ditch your Klone and move elsewhere, all your disk can come with you. With IDE, you're stuck with buying another Klone. 4) You can hang _lots_ of things off a SCSI bus. You can also have some of them outside your system unit. With IDE you're basically restricted to disks and CDs. That'll do for now; there are more. > Serge. -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] My car has "demand start" -Terry Lambert UNIX: live FreeBSD or die! [[