From owner-freebsd-stable@FreeBSD.ORG Thu Jan 17 15:23:57 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0CF7016A41A; Thu, 17 Jan 2008 15:23:57 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from falcon.cybervisiontech.com (falcon.cybervisiontech.com [217.20.163.9]) by mx1.freebsd.org (Postfix) with ESMTP id D09B513C447; Thu, 17 Jan 2008 15:23:56 +0000 (UTC) (envelope-from avg@icyb.net.ua) Received: from localhost (localhost [127.0.0.1]) by falcon.cybervisiontech.com (Postfix) with ESMTP id 88D17744021; Thu, 17 Jan 2008 17:23:54 +0200 (EET) X-Virus-Scanned: Debian amavisd-new at falcon.cybervisiontech.com Received: from falcon.cybervisiontech.com ([127.0.0.1]) by localhost (falcon.cybervisiontech.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id v6auR7+N8nks; Thu, 17 Jan 2008 17:23:54 +0200 (EET) Received: from [10.2.1.87] (gateway.cybervisiontech.com.ua [88.81.251.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by falcon.cybervisiontech.com (Postfix) with ESMTP id 2E921744002; Thu, 17 Jan 2008 17:23:54 +0200 (EET) Message-ID: <478F7309.4040606@icyb.net.ua> Date: Thu, 17 Jan 2008 17:23:53 +0200 From: Andriy Gapon User-Agent: Thunderbird 2.0.0.9 (X11/20071116) MIME-Version: 1.0 To: freebsd-scsi@freebsd.org, freebsd-stable@freebsd.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Subject: cd(4) as compared to acd(4) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jan 2008 15:23:57 -0000 It seems that cd driver lacks couple of useful features as compared to acd: 1. device nodes for individual tracks: this might not be so useful for tracks on audio CDs, but it is especially useful for mixed audio/data CDs and multi-track data CDs; 2. automatic detection of track type (audio/data) and then using proper READ command (e.g. READ CD) in strategy, so that read(2) works even for audio CDs (convenient and easy way of doing digital audio extraction); The second one also breaks "API" compatibility between the drivers: if you want to do digital audio extraction, you have to know underlying device type and use different techniques. It seems that these features are not terribly hard to implement (using acd as an example). I am not volunteering at this moment, but this could be added to some "junior hacker tasks" list. -- Andriy Gapon