From owner-freebsd-questions@FreeBSD.ORG Thu May 24 13:16:36 2007 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id ACC1B16A400 for ; Thu, 24 May 2007 13:16:36 +0000 (UTC) (envelope-from mailist@whoweb.com) Received: from whoweb.com (whoweb.com [66.180.172.55]) by mx1.freebsd.org (Postfix) with ESMTP id 5E52413C448 for ; Thu, 24 May 2007 13:16:36 +0000 (UTC) (envelope-from mailist@whoweb.com) Received: from whoweb.com (localhost [127.0.0.1]) by whoweb.com (8.13.8/8.13.8) with ESMTP id l4OCxlqQ055743 for ; Thu, 24 May 2007 08:59:47 -0400 (EDT) Received: (from mailist@localhost) by whoweb.com (8.13.8/8.13.8/Submit) id l4OCxliV055742 for freebsd-questions@freebsd.org; Thu, 24 May 2007 08:59:47 -0400 (EDT) Date: Thu, 24 May 2007 08:59:47 -0400 (EDT) From: Incoming Mail List Message-Id: <200705241259.l4OCxliV055742@whoweb.com> To: freebsd-questions@freebsd.org Subject: can't read raw CD device X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2007 13:16:36 -0000 Hello, I'm trying to understand why I cannot read my CD drive directly from a 'c' program using the read(2) system call, or even using the dd(1) command. As you will see, I have both the acd0 and cd0 devices since I have atapicam configured in the kernel. I can mount cdrom media using mount() and access data via the cd9660 file system, so I know the drive and the media are not the problem. #dd if=/dev/acd0 of=/dev/null count=20 dd: /dev/acd0: Invalid argument 0+0 records in 0+0 records out 0 bytes transferred in 0.000163 secs (0 bytes/sec) #dd if=/dev/cd0 of=/dev/null count=20 dd: /dev/cd0: Invalid argument 0+0 records in 0+0 records out 0 bytes transferred in 0.000179 secs (0 bytes/sec) Thanks, Jon