From owner-freebsd-questions@FreeBSD.ORG Thu Aug 18 15:15:25 2005 Return-Path: X-Original-To: questions@FreeBSD.org Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C970D16A41F for ; Thu, 18 Aug 2005 15:15:25 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from pi.codefab.com (pi.codefab.com [199.103.21.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id 73A1B43D45 for ; Thu, 18 Aug 2005 15:15:25 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from localhost (localhost [127.0.0.1]) by pi.codefab.com (Postfix) with ESMTP id C5E515C74; Thu, 18 Aug 2005 11:15:24 -0400 (EDT) Received: from pi.codefab.com ([127.0.0.1]) by localhost (pi.codefab.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 47246-07; Thu, 18 Aug 2005 11:15:23 -0400 (EDT) Received: from [192.168.1.3] (pool-68-161-79-217.ny325.east.verizon.net [68.161.79.217]) by pi.codefab.com (Postfix) with ESMTP id CFD385C5B; Thu, 18 Aug 2005 11:15:18 -0400 (EDT) Message-ID: <4304A60A.6060003@mac.com> Date: Thu, 18 Aug 2005 11:15:22 -0400 From: Chuck Swiger Organization: The Courts of Chaos User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.11) Gecko/20050801 X-Accept-Language: en-us, en MIME-Version: 1.0 To: cdiscepola@encentrus.com References: <1124376046.3696.6.camel@localhost.localdomain> In-Reply-To: <1124376046.3696.6.camel@localhost.localdomain> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: amavisd-new at codefab.com Cc: questions@FreeBSD.org Subject: Re: blanking DVD+RW 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, 18 Aug 2005 15:15:25 -0000 Claudio Discepola wrote: > I have a quick question about blanking a DVD+RW. It seems that even > after I run the "growisofs -Z /dev/cd0=/dev/zero" command the "Disc > status" is still seen as "complete" instead of "blank". Simply using dvd+rw-format doesn't erase all of the previous contents of the DVD, whereas overwriting with zeros as you've done will obscure the old data reasonably well. There is a difference between a disk which has never been written to, and a disk which has been written full of zeros. Note that someone with the right forensics technology probably could read a zeroed DVD, the same way you can read most of the data from a hard drive even after a single erasure pass. -- -Chuck