From owner-freebsd-questions@FreeBSD.ORG Thu Oct 11 02:06:08 2012 Return-Path: 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 904AB91B for ; Thu, 11 Oct 2012 02:06:08 +0000 (UTC) (envelope-from wblock@wonkity.com) Received: from wonkity.com (wonkity.com [67.158.26.137]) by mx1.freebsd.org (Postfix) with ESMTP id 492CD8FC08 for ; Thu, 11 Oct 2012 02:06:08 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.5/8.14.5) with ESMTP id q9B267xu038204 for ; Wed, 10 Oct 2012 20:06:07 -0600 (MDT) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.5/8.14.5/Submit) with ESMTP id q9B267Lx038201 for ; Wed, 10 Oct 2012 20:06:07 -0600 (MDT) (envelope-from wblock@wonkity.com) Date: Wed, 10 Oct 2012 20:06:07 -0600 (MDT) From: Warren Block To: freebsd-questions@freebsd.org Subject: Re: DVD OPC errors with growisofs In-Reply-To: <20121008113341.2f040b54@fabiankeil.de> Message-ID: References: <20121008113341.2f040b54@fabiankeil.de> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (wonkity.com [127.0.0.1]); Wed, 10 Oct 2012 20:06:07 -0600 (MDT) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Oct 2012 02:06:08 -0000 On Mon, 8 Oct 2012, Fabian Keil wrote: > Warren Block wrote: > >> I'm using growisofs to write DVDs of backup files. Some combinations of >> older drives and newer media give ":-( unable to PERFORM OPC: >> Input/output error". > > If you are concerned about this, you could try cdrecord > to see if it makes a difference. > >> Can limiting write speed avoid these errors? > > That depends on both the drive and the media. > It's also possible that it makes matters worse, though. > > It's a myth that reducing speed guarantees better results. > >> And what ways are there to >> detect the fastest speed supported by both drive and media? > > The drive is supposed to figure it out on its own. > > If your drive supports it, you can use readcd to measure how > well burned media can be read and do a couple of experiments > with various burn speeds to see if it affects the results for > your drives and the media you care about. The plot thickens. These OPC errors appeared on several older (2006) IDE DVD drives connected through various USB to IDE adapters. Connected to an actual IDE controller, no errors. The USB system not passing something through that it should, maybe. Or possibly the USB to IDE hardware, but that seems less likely.