From owner-freebsd-arch@FreeBSD.ORG Mon Oct 6 15:20:11 2003 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9038616A4BF for ; Mon, 6 Oct 2003 15:20:11 -0700 (PDT) Received: from shockwave.systems.pipex.net (shockwave.systems.pipex.net [62.241.160.9]) by mx1.FreeBSD.org (Postfix) with ESMTP id A72C843F75 for ; Mon, 6 Oct 2003 15:20:10 -0700 (PDT) (envelope-from mark@thuvia.org) Received: from dotar.thuvia.org (81-86-228-29.dsl.pipex.com [81.86.228.29]) by shockwave.systems.pipex.net (Postfix) with ESMTP id 4106A1C0095B; Mon, 6 Oct 2003 23:20:08 +0100 (BST) Received: from dotar.thuvia.org (localhost [127.0.0.1]) by dotar.thuvia.org (8.12.9/8.12.9) with ESMTP id h96MK7PA061402; Mon, 6 Oct 2003 23:20:07 +0100 (BST) (envelope-from mark@dotar.thuvia.org) Received: (from mark@localhost) by dotar.thuvia.org (8.12.9/8.12.9/Submit) id h96MK7PI061345; Mon, 6 Oct 2003 23:20:07 +0100 (BST) (envelope-from mark) Message-Id: <200310062220.h96MK7PI061345@dotar.thuvia.org> From: Mark Valentine Date: Mon, 6 Oct 2003 23:20:06 +0000 In-Reply-To: X-Mailer: Mail User's Shell (7.2.6 beta(5) 10/07/98) To: wollman@khavrinen.lcs.mit.edu (Garrett Wollman), phk@phk.freebsd.dk cc: arch@freebsd.org Subject: Re: Alignment of disk-I/O from userland. X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 06 Oct 2003 22:20:11 -0000 > From: wollman@khavrinen.lcs.mit.edu (Garrett Wollman) > Date: Mon 6 Oct, 2003 > Subject: Re: Alignment of disk-I/O from userland. > I believe that the Standard allows practically arbitrary restrictions > on what may be done with devices (since most devices, aside from ttys, > are outside the scope of the Standard anyway). It says that read() > may fail if: > > [ENXIO] A request was made of a nonexistent device, or the request > was outside the capabilities of the device. Hmm, but it doesn't say: [EDOOFUS] A request was made of a nonexistent device, or the request was outside the capabilities of the device driver writer. It would be reasonable to enforce such restrictions on a raw device if we still had block devices around, but it doesn't seem reasonable now. Cheers, Mark. -- "Tigers will do ANYTHING for a tuna fish sandwich." "We're kind of stupid that way." *munch* *munch* --