From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262551AbTJGRxV (ORCPT ); Tue, 7 Oct 2003 13:53:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262553AbTJGRxV (ORCPT ); Tue, 7 Oct 2003 13:53:21 -0400 Received: from mail.kroah.org ([65.200.24.183]:57834 "EHLO perch.kroah.org") by vger.kernel.org with ESMTP id S262551AbTJGRxS (ORCPT ); Tue, 7 Oct 2003 13:53:18 -0400 Date: Tue, 7 Oct 2003 10:53:10 -0700 From: Greg KH To: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= Cc: linux-kernel@vger.kernel.org Subject: Re: devfs vs. udev Message-ID: <20031007175310.GC1956@kroah.com> Reply-To: linux-kernel@vger.kernel.org References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 07, 2003 at 02:38:27PM +0200, Måns Rullgård wrote: > > I noticed this in the help text for devfs in 2.6.0-test6: > > Note that devfs has been obsoleted by udev, > . > It has been stripped down to a bare minimum and is only provided for > legacy installations that use its naming scheme which is > unfortunately different from the names normal Linux installations > use. > > Now, this puzzles me, for a few of reasons. Firstly, not long ago, > devfs was spoken of as the way to go, and all drivers were rewritten > to support it. Why this sudden change? A few things happened: - the devfs maintainer/author disappeared and stoped maintaining the code. - devfs was found to have unfixable bugs - it was determined that the same thing could be done in userspace (like udev.) > Secondly, that link only leads me to a package describing itself as an > experimental proof-of-concept thing, not to be used for anything > serious. How can something that incomplete obsolete a working system > like devfs? I didn't send that patch to the kernel to mark devfs as such. Actually devfs is still very much "experimental" and "proof-of-concept" if you have ever looked at it's code :) > Thirdly, udev appears to respond to hotplug events only. How is it > supposed to handle device files not corresponding to any physical > device? Like what? Anything that shows up in sysfs, udev will handle. It's only a matter of getting everything to show up in sysfs now... It's almost all there. > Finally, I quite liked the idea of a virtual filesystem for /dev. It > reduced the clutter quite a bit. As for the naming scheme, it could > easily be changed. devfs's naming scheme could easily be changed? Hahaha... udev will be a major factor of improvement for changable naming schemes. Please read the OLS paper for more details. thanks, greg k-h