From owner-freebsd-questions@FreeBSD.ORG Thu Feb 12 23:13:46 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 32D09106564A for ; Thu, 12 Feb 2009 23:13:46 +0000 (UTC) (envelope-from utisoft@googlemail.com) Received: from wf-out-1314.google.com (wf-out-1314.google.com [209.85.200.175]) by mx1.freebsd.org (Postfix) with ESMTP id 016A38FC1A for ; Thu, 12 Feb 2009 23:13:45 +0000 (UTC) (envelope-from utisoft@googlemail.com) Received: by wf-out-1314.google.com with SMTP id 27so884826wfd.7 for ; Thu, 12 Feb 2009 15:13:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:reply-to:in-reply-to :references:date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=nlG7jCJ8q/+Hfntu9MdDqbU+zBfg85kjKofIxynEfxY=; b=SuGf22tHwcRi4nkDJfIFRT6KTgXzCLBYLwC3Px1scakR82w5ChEjFF+fahAgCVKjS3 9BOc0VySoJwlDz5OefQDt7UqwyxUtCiUMzcZTUoSSg03guNisMEBN4kuLtp2oB7glBVb lgFVbE96vJtj+WACICmdyASXX9TZ/84NsAUFo= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:reply-to:in-reply-to:references:date:message-id :subject:from:to:cc:content-type:content-transfer-encoding; b=ISnx95DoABDrEt2kaL2ULC4tQcCThN7Q4TccwsHp32lQO7VZ59n21P9xvCa/jYtlY8 mMLvgo5CLu89zkfdVdqDnGk5nRiVYVIEJGNtolA7GGT5fcFsKuhVK6MeEuTSv2RwTDvO vwMrUrAzdp0fE/C8kwvMawKD1dwlYviFfqZ1g= MIME-Version: 1.0 Received: by 10.142.158.3 with SMTP id g3mr218139wfe.333.1234480425514; Thu, 12 Feb 2009 15:13:45 -0800 (PST) In-Reply-To: <20090212235111.D97916@wojtek.tensor.gdynia.pl> References: <1234423939.27702.4.camel@ethos> <20090212101453.I81232@wojtek.tensor.gdynia.pl> <20090212105424.a710de5e.freebsd@edvax.de> <20090212141444.W81609@wojtek.tensor.gdynia.pl> <4994919E.3000803@gmail.com> <20090212235111.D97916@wojtek.tensor.gdynia.pl> Date: Thu, 12 Feb 2009 23:13:45 +0000 Message-ID: From: Chris Rees To: Wojciech Puchar Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Tim Judd , Gary Kline , Polytropon , FreeBSD Mailing List Subject: Re: How-to erase a DVD-RW X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: utisoft@gmail.com List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Feb 2009 23:13:46 -0000 2009/2/12 Wojciech Puchar : >>> which is exactly what i suggested - writing 0 byte disc >> >> >> that writes binary 0, the ASCII "NUL" character. /dev/zero is NOT a >> zero-size file. > > yes it is > > [wojtek@wojtek ~/NOBACKUP]$ dd if=/dev/null of=/dev/null bs=1 > 0+0 records in > 0+0 records out > 0 bytes transferred in 0.000037 secs (0 bytes/sec) > > > /dev/null simply gives EOF when trying to read But we're talking about /dev/zero, not /dev/null ... [chris@zeus]~% dd if=/dev/zero of=/dev/null bs=2 count=5 5+0 records in 5+0 records out 10 bytes transferred in 0.000050 secs (200684 bytes/sec) [chris@zeus]~% Chris -- R< $&h ! > $- ! $+ $@ $2 < @ $1 .UUCP. > (sendmail.cf)