From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from <gentoo-user+bounces-136288-garchives=archives.gentoo.org@lists.gentoo.org>) id 1S7a78-00040f-6L for garchives@archives.gentoo.org; Tue, 13 Mar 2012 22:22:42 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 812ABE0CC0; Tue, 13 Mar 2012 22:22:27 +0000 (UTC) Received: from mail.muc.de (colin.muc.de [193.149.48.1]) by pigeon.gentoo.org (Postfix) with ESMTP id A9793E0AF8 for <gentoo-user@lists.gentoo.org>; Tue, 13 Mar 2012 22:21:19 +0000 (UTC) Received: (qmail 54618 invoked by uid 3782); 13 Mar 2012 22:21:18 -0000 Received: from acm.muc.de (pD951B273.dip.t-dialin.net [217.81.178.115]) by colin.muc.de (tmda-ofmipd) with ESMTP; Tue, 13 Mar 2012 23:21:14 +0100 Received: (qmail 5218 invoked by uid 1000); 13 Mar 2012 22:20:19 -0000 Date: Tue, 13 Mar 2012 22:20:19 +0000 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Beta test Gentoo with mdev instead of udev; version 5 - failure :-( Message-ID: <20120313222019.GE2536@acm.acm> References: <20120217234045.GA25390@waltdnes.org> <20120311090912.GA23850@waltdnes.org> <20120312092432.GA2959@acm.acm> <20120313073306.GC23544@waltdnes.org> <20120313130534.GB3457@acm.acm> <20120313190052.GA2430@waltdnes.org> <20120313194727.GB2536@acm.acm> <CADPrc83mmaeybgdEb0phBrp=fBcF3EWkpZawp0Mo8wpvDje5NQ@mail.gmail.com> <20120313210737.GD2536@acm.acm> <20120313213330.78c5ebf7@digimed.co.uk> Precedence: bulk List-Post: <mailto:gentoo-user@lists.gentoo.org> List-Help: <mailto:gentoo-user+help@lists.gentoo.org> List-Unsubscribe: <mailto:gentoo-user+unsubscribe@lists.gentoo.org> List-Subscribe: <mailto:gentoo-user+subscribe@lists.gentoo.org> List-Id: Gentoo Linux mail <gentoo-user.gentoo.org> X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120313213330.78c5ebf7@digimed.co.uk> User-Agent: Mutt/1.5.21 (2010-09-15) X-Delivery-Agent: TMDA/1.1.12 (Macallan) From: Alan Mackenzie <acm@muc.de> X-Primary-Address: acm@muc.de X-Archives-Salt: fca05d10-7283-431a-aba8-1b38d56db65c X-Archives-Hash: 358a658c9f5a60d4671c8ff459ee89f5 Hello, Neil. On Tue, Mar 13, 2012 at 09:33:30PM +0000, Neil Bothwick wrote: > On Tue, 13 Mar 2012 21:07:37 +0000, Alan Mackenzie wrote: > > But I really meant what functionality udev has that mdev lacks. For > > example, mdev this morning recognised my USB stick being inserted, and > > created /dev/sdc for it. > udev does a *lot* more than that, for example the persistent naming of > network interfaces. More significantly, it can run programs based on > device rules. This is where I start getting unhappy. Is there any need for this blurring? Having device nodes is essential to a linux system, and some programs use these nodes. Why must they be mashed together into a tasteless mush? Is there some advantage to this I haven't twigged yet? > For example, usb_modeswitch installs a udev rule to switch a 3G USB > modem from CD to modem mode, without which it won't work. Same question as above: why does that switching have to be done via the device node system rather than via the driver. Isn't that what drivers are for? > That's fine when you plug it into a running system, but when you boot > with it plugged in, it can trip over itself because the usb_modeswitch > executable is in /usr/sbin. Er, that's a different discussion altogether. ;-) > You could use this to argue that /usr should be mounted before udev is > started, but you could just as well use it to argue that udev should not > be trying to run such rules at the boot runlevel. Or that udev shouldn't have "rules". I still don't understand the basic concept driving this thing. My HDDs don't need rules - they just need a mapping from /dev/sd[ab] into device 8/0 and 8/16, and the appropriate drivers built into my kernel. Am I being stupid? Despite your example above, I still don't see what udev is about, why it's necessary, or even why it's advantageous. > -- > Neil Bothwick -- Alan Mackenzie (Nuremberg, Germany).