From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=37457 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OQI89-0007P4-1o for qemu-devel@nongnu.org; Sun, 20 Jun 2010 06:52:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OQI7y-0006rJ-O4 for qemu-devel@nongnu.org; Sun, 20 Jun 2010 06:51:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9124) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OQI7y-0006rA-Hd for qemu-devel@nongnu.org; Sun, 20 Jun 2010 06:51:50 -0400 Message-ID: <4C1DF2C1.5040505@redhat.com> Date: Sun, 20 Jun 2010 13:51:45 +0300 From: Avi Kivity MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: block: format vs. protocol, and how they stack List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Kevin Wolf , Christoph Hellwig , qemu-devel@nongnu.org, Luiz Capitulino , Gerd Hoffmann On 06/18/2010 03:59 PM, Markus Armbruster wrote: > The code is pretty confused about format vs. protocol, and so are we. > Let's try to figure them out. > > From cruising altitude, all this format, protocol, stacking business > doesn't matter. We provide a bunch of arguments, and get an image. > > If you look more closely, providing that image involves sub-tasks. One > is to haul bits. Another one is to translate between bits in different > formats. > > Working hypothesis: > > * A protocol hauls image bits. Examples: file, host_device, nbd. > > * A format translates image formats. Examples: raw, qcow2. > > Is there a reason to make the distinction? Is there a reason to expose the distinction to the user? -- error compiling committee.c: too many arguments to function