From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265051AbUHHEIe (ORCPT ); Sun, 8 Aug 2004 00:08:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265074AbUHHEIe (ORCPT ); Sun, 8 Aug 2004 00:08:34 -0400 Received: from hibernia.jakma.org ([212.17.55.49]:56704 "EHLO hibernia.jakma.org") by vger.kernel.org with ESMTP id S265051AbUHHEIc (ORCPT ); Sun, 8 Aug 2004 00:08:32 -0400 Date: Sun, 8 Aug 2004 05:07:53 +0100 (IST) From: Paul Jakma X-X-Sender: paul@fogarty.jakma.org To: Joerg Schilling cc: mj@ucw.cz, James.Bottomley@steeleye.com, axboe@suse.de, linux-kernel@vger.kernel.org Subject: Re: PATCH: cdrecord: avoiding scsi device numbering for ide devices In-Reply-To: <200408071053.i77Aromi006941@burner.fokus.fraunhofer.de> Message-ID: References: <200408071053.i77Aromi006941@burner.fokus.fraunhofer.de> X-NSA: arafat al aqsar jihad musharef jet-A1 avgas ammonium qran inshallah allah al-akbar martyr iraq saddam hammas hisballah rabin ayatollah korea vietnam revolt mustard gas british airways washington MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 7 Aug 2004, Joerg Schilling wrote: > 5) Take a look at /etc/path_to_inst and call "man path_to_inst" The irony here is that the kernel you point at does *not* try to map unrelated busses into the same namespace, that the tools and files like path_to_inst exist precisely to deal with the fact that topology information is no more than ephemereal, and that even the end-user device naming does *not* try to map IDE into SCSI. That the /dev/dsk names typically encode some *logical* topology information into the names is beside the point, it's just the Solaris convention, the real point is that they abstract the device location, so that the user is not required to know that their disk is really at, eg: /devices/pci@0,0/pci-ide@7,1/ide@1/sd@0,0:d,raw Which is where the /dev/ node would symlink to. The /dev/ name has nothing to do with physical topology (though might be vaguely similar). Also note that the logical /dev/ symlink name is encoded *differently* for IDE versus SCSI. Trying to plaster SCSI notations into IDE topology is just not useful. Indeed, some devices are not dependent on topology at all, they depend on some other topology independent identifier, eg FC UUID. Having user utilities try invent their own namespace, inconsistent with both the physical topology and the system's conventions is even less useful. regards, -- Paul Jakma paul@clubi.ie paul@jakma.org Key ID: 64A2FF6A Fortune: QOTD: "I drive my car quietly, for it goes without saying."