From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265887AbUHHQps (ORCPT ); Sun, 8 Aug 2004 12:45:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265893AbUHHQps (ORCPT ); Sun, 8 Aug 2004 12:45:48 -0400 Received: from stat16.steeleye.com ([209.192.50.48]:27288 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S265887AbUHHQpq (ORCPT ); Sun, 8 Aug 2004 12:45:46 -0400 Subject: Re: PATCH: cdrecord: avoiding scsi device numbering for ide devices From: James Bottomley To: Joerg Schilling Cc: Jens Axboe , Linux Kernel In-Reply-To: <200408061330.i76DU2Tm005937@burner.fokus.fraunhofer.de> References: <200408061330.i76DU2Tm005937@burner.fokus.fraunhofer.de> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-9) Date: 08 Aug 2004 11:45:27 -0500 Message-Id: <1091983528.10960.7.camel@mulgrave> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2004-08-06 at 08:30, Joerg Schilling wrote: > I don't see any arrogance in my mails but in former discussions on LKML, > there have been other people who did believe that they could replace missing > knowledge by arrogance. Fortunately, they did not join this thread ;-) > > Let me lead you to the right place to look for: > > The CAM interface (which is from the SCSI standards group) > usually is implemeted in a way that applications open /dev/cam and > later supply bus, target and lun in order to get connected > to any device on the system that talks SCSI. > > Let me repeat: If you believe that this is a bad idea, give very good reasons. Although I have always thought CAM to be a bad idea, I can give you the best of reasons why we won't be using it: The old standard applies to SCSI-2 and has been superceded. The committee charged with creating the new CAM standard was disbanded in disarray, so there is no current CAM standard. I know all the arguments about politics and personality clashes that have been alleged to be behind the collapse of the new standard. However, in my view, it was a bad standard and the evidence of its unworkability is simply that the committee couldn't agree on it. For us to look at CAM again, someone will have to at least make it a current standard. The model which looks to me to be very workable is SAM (or at least SAM-3). To that end, we're already moving the linux scsi layer (which was actually pretty transport abstracted and thus SAM conformant anyway) further in that direction with the creation of transport classes. James