From owner-freebsd-arch@FreeBSD.ORG Mon Oct 6 15:22:11 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 3665E16A4B3 for ; Mon, 6 Oct 2003 15:22:11 -0700 (PDT) Received: from khavrinen.lcs.mit.edu (khavrinen.lcs.mit.edu [18.24.4.193]) by mx1.FreeBSD.org (Postfix) with ESMTP id 47A1543FE3 for ; Mon, 6 Oct 2003 15:22:08 -0700 (PDT) (envelope-from wollman@khavrinen.lcs.mit.edu) Received: from khavrinen.lcs.mit.edu (localhost [IPv6:::1]) by khavrinen.lcs.mit.edu (8.12.9/8.12.9) with ESMTP id h96MM6gk093686 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK CN=khavrinen.lcs.mit.edu issuer=SSL+20Client+20CA); Mon, 6 Oct 2003 18:22:07 -0400 (EDT) (envelope-from wollman@khavrinen.lcs.mit.edu) Received: (from wollman@localhost) by khavrinen.lcs.mit.edu (8.12.9/8.12.9/Submit) id h96MM6MO093683; Mon, 6 Oct 2003 18:22:06 -0400 (EDT) (envelope-from wollman) Date: Mon, 6 Oct 2003 18:22:06 -0400 (EDT) From: Garrett Wollman Message-Id: <200310062222.h96MM6MO093683@khavrinen.lcs.mit.edu> To: Mark Valentine In-Reply-To: <200310062220.h96MK7PI061345@dotar.thuvia.org> References: <200310062220.h96MK7PI061345@dotar.thuvia.org> X-Spam-Score: -19.8 () IN_REP_TO,QUOTED_EMAIL_TEXT,REFERENCES,REPLY_WITH_QUOTES X-Scanned-By: MIMEDefang 2.37 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 22:22:11 -0000 < said: > 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. I think you've got that backwards. When we had block devices, they would provide extra buffering to avoid I/O-size breakage. Character devices, which are all we have now, never made any promises. -GAWollman