Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 5 Nov 2002 23:41:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 5 Nov 2002 23:41:50 -0500 Received: from leibniz.math.psu.edu ([146.186.130.2]:43231 "EHLO math.psu.edu") by vger.kernel.org with ESMTP id ; Tue, 5 Nov 2002 23:41:49 -0500 Date: Tue, 5 Nov 2002 23:48:25 -0500 (EST) From: Alexander Viro To: Mike Diehl cc: kcorry@austin.rr.com, evms-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [Evms-devel] EVMS announcement In-Reply-To: <20021106022549.C849B55A9@dominion.dyndns.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1684 Lines: 33 On Tue, 5 Nov 2002, Mike Diehl wrote: > Na, I can't ignore the debate. I can't wait to see how user-land descovery > will be implemented. There is something intrinsically "nice" about having an > OS automatically discover every aspect of a machine I'm installing on. I Kernel _can't_ do that. In principle. Simply because part of the kernel that would know how to talk with that PCI card (which just happens to be a SCSI adapter) happens to be a module that lives on a filesystem that lives on a different server and will be accessible only after we configure this NIC. There is no way in hell to tell what devices sit on the SCSI bus behind that card. Not without userland participation in the process. So like it or not, userland is involved. The best thing that can be done is exposing the list of block devices (with information about them) that kernel knows of + passing events (device added/removed/etc.) to userland. We have both - one in sysfs and another as calls of /sbin/hotplug. What's more, we are about to get them very early, so a lot of warts become not necessary (all drivers' setup happens with early userland already in place, so we the things that had to be done manually can use generic mechanisms). Note that both interfaces are still changing and figuring out what is really needed will certainly be easier with non-trivial users of these mechanisms. EVMS definitely will be one of such users... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/