From owner-freebsd-hackers@FreeBSD.ORG Mon Sep 29 00:58:16 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DB91E16A4C4 for ; Mon, 29 Sep 2003 00:58:16 -0700 (PDT) Received: from c211-28-27-130.belrs2.nsw.optusnet.com.au (c211-28-27-130.belrs2.nsw.optusnet.com.au [211.28.27.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3D35343FE1 for ; Mon, 29 Sep 2003 00:58:15 -0700 (PDT) (envelope-from peterjeremy@optushome.com.au) Received: from server.c211-28-27-130.belrs2.nsw.optusnet.com.au (localhost.c211-28-27-130.belrs2.nsw.optusnet.com.au [127.0.0.1]) ESMTP id h8T7wAdb003203; Mon, 29 Sep 2003 17:58:10 +1000 (EST) peter@server.c211-28-27-130.belrs2.nsw.optusnet.com.au) Received: (from peter@localhost) (8.12.9p1/8.12.9/Submit) id h8T7wAWM003202; Mon, 29 Sep 2003 17:58:10 +1000 (EST) (envelope-from peter) Date: Mon, 29 Sep 2003 17:58:10 +1000 From: Peter Jeremy To: Sergey Babkin Message-ID: <20030929075809.GA3062@server.c211-28-27-130.belrs2.nsw.optusnet.com.au> References: <3F775D41.DF780001@bellatlantic.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3F775D41.DF780001@bellatlantic.net> User-Agent: Mutt/1.4.1i cc: hackers@freebsd.org Subject: Re: has anyone installed 5.1 from a SCSI CD? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Sep 2003 07:58:17 -0000 On Sun, Sep 28, 2003 at 06:14:25PM -0400, Sergey Babkin wrote: >BTW, I have another related issue too: since at least 4.7 >all the disk device nodes have charcater device entries in /dev. As of December 1999 - which is before 4.0-RELEASE. This was well advertised and discussed at the time. Your objections are about 4 years too late. >That's very, very wrong. Even though there may be no difference >any more between the charcater and block drivers, the type of >device node still conveys the information about device types >to the applications. One case in point being a viewer application >(if anyone is interested, http://nac.sf.net ) which must handle >the sequential and random-access devices differently: 'block' vs 'character' has nothing to do with random or sequential access and any application that thinks it does is broken. Any application that directly accesses devices must understand all the various quirks - ability to seek, block size(s) supported, side- effects of operations etc. Yes, block devices must be random access, but character devices can be either random or sequential-only depending on the physical device. The only purpose for block devices was to provide a cache for disk devices. It makes far more sense for this caching to be tightly coupled into the filesystem code where the cache characteristics can be better controlled. Peter