With the announcement of udev 018, Greg KH noted that at this time he is running with udev [story] managing the /dev directory on his primary email and development server. He says, "this is a major milestone for udev and it proves that it is a viable solution," going on to add, "udev development isn't done, but for anyone who has not checked it out yet, I suggest you do so."

To make the task of trying udev a little easier, Greg has released a short howto. He says:

"Here's a small document that I've added to the udev tarball that explains how I managed to get udev to manage my /dev tree on a Red Hat Fedora based machine. All you Gentoo developers can just laugh as it's already integrated into your distro."

From: Greg KH [email blocked]
To:  linux-hotplug-devel, [email blocked]
Subject: [ANNOUNCE] udev 018 release
Date: Thu, 19 Feb 2004 10:59:32 -0800

I've released the 018 version of udev.  It can be found at:
 	kernel.org/pub/linux/utils/kernel/hotplug/udev-018.tar.gz

rpms built against Red Hat FC2-test1 are available at:
	kernel.org/pub/linux/utils/kernel/hotplug/udev-018-1.i386.rpm
with the source rpm at:
	kernel.org/pub/linux/utils/kernel/hotplug/udev-018-1.src.rpm

udev allows users to have a dynamic /dev and provides the ability to
have persistent device names.  It uses sysfs and /sbin/hotplug and runs
entirely in userspace.  It requires a 2.6 kernel with CONFIG_HOTPLUG
enabled to run.  Please see the udev FAQ for any questions about it:
	kernel.org/pub/linux/utils/kernel/hotplug/udev-FAQ

For any udev vs devfs questions anyone might have, please see:
	kernel.org/pub/linux/utils/kernel/hotplug/udev_vs_devfs


Major changes from the 017 version:
	- We now handle the ability to generate all partitions for a
	  device to allow removable devices to work in a sane manner.
	  This has been requested by a lot of people.
	- there's a new %s{} modifier available for people to use
	- the SYSFS_ style rule has changed to SYSFS{}.  The old style
	  is still supported for now, but you have been warned
	- %c1 style modifiers has been changed to %c{1}.  Again, the old
	  style format still works.
	- scsi_id is built by default now in the rpm and is available in
	  the pre-built rpm package.  This should get it a wider range
	  of testing.
	- lots of bug fixes and other cleanups.

In all, there is nothing hugely major in this release, but any current
users of udev will want this version for all of the bugfixes if for
nothing else.

Thanks to everyone who has send me patches for this release, a full list
of everyone, and their changes is below.

udev development is done in a BitKeeper repository located at:
	bk://linuxusb.bkbits.net/udev

Daily snapshots of udev from the BitKeeper tree can be found at:
	http://www.codemonkey.org.uk/projects/bitkeeper/udev/
If anyone ever wants a tarball of the current bk tree, just email me.

thanks,

greg k-h

Summary of changes from v017 to v018
============================================

<ext.devoteam.varoqui:sncf.fr>:
  o [PATCH] symlink dm-[0-9]* rule
  o update extras/multipath

<john-hotplug:fjellstad.org>:
  o init.d debian patch

Kay Sievers:
  o udev - TODO update
  o udev - add %s{filename} to man page
  o udev - udevd/udevsend man page
  o udev - switch callout part selector to {attribute}
  o udev - switch SYSFS_file to SYSFS{file}
  o udev - create all partitions of blockdevice
  o allow SYSFS{file}
  o Adding '%s' format specifier to NAME and SYMLINK

Greg Kroah-Hartman:
  o added some scsi_id files to the bk ignore file
  o added scsi_id and some more documentation to the udev.spec file
  o update udev.rules.gentoo with new config file format
  o Update the Gentoo udev.rules and udev.permissions files
  o Create a udev.rules.examples file to hold odd udev.rules
  o add udevd priority issue to the TODO list
  o more HOWTO cleanups
  o add HOWTO detailing how to use udev to manage /dev
  o mv libsysfs/libsysfs.h to libsysfs/sysfs/libsysfs.h to make it easier to use
  o add start_udev init script
  o add support for UDEV_NO_SLEEP env variable so Gentoo people will be happy
  o start up udevd ourselves in the init script to give it some good priorities
  o update the red hat init script to handle nodes that are not present
  o add a "old style" SYSFS_attribute test to udev-test.pl
  o Have udevsend report more info in debug mode
  o Have udevd report it's version in debug mode
  o fix up bug created for udevtest in previous partition creation patch
  o update the udev.spec to add udevtest and make some more Red Hat suggested changes
  o add ability to install udevtest to Makefile
  o 017_bk mark
  o Add another test to udev-test.pl and fix a bug when only running 1 test
  o Fix bug where we did not use the "converted" kernel name if we had no rule
  o v017 release TAG: v017

Patrick Mansfield:
  o udev use new libsysfs header file location
  o udev add some ID tests



From: Greg KH [email blocked]
Subject: Re: [ANNOUNCE] udev 018 release
Date: Thu, 19 Feb 2004 11:13:15 -0800

On Thu, Feb 19, 2004 at 10:59:32AM -0800, Greg KH wrote:
> I've released the 018 version of udev.  It can be found at:
>  	kernel.org/pub/linux/utils/kernel/hotplug/udev-018.tar.gz

As of this release, I've been running with udev managing my /dev for me
exclusively on my main email and development machine.  This is a major
milestone for udev and it proves that it is a viable solution.

I'd like to say thanks to everyone who has made this possible to do:
	- Pat Mochel for creating sysfs and listening to my crazy ideas
	  about how we could create a userspace devfs all those years
	  ago.
	- Dan Stekloff for prodding me to actually implement this crazy
	  idea and who came up with a solid initial design document,
	  without which this project would have never left the dream
	  stage.
	- Kay Sievers for almost single-handedly taking over the whole
	  udev TODO list and converting udev from a small "proof of
	  concept" toy into a powerful and useful tool.
	- Pat Mansfield for creating the scsi_id tool and enabling udev
	  to call external programs, which instantly made udev a real
	  tool in the fine Unix tradition.
	- All of the Gentoo developers who integrated udev into their
	  distro and showed me that it can actually run a machine.
	- everyone who has sent in udev patches, bug reports, and
	  feature requests.  Without these udev would only work for me,
	  and not the rest of the world.  A community is very important.
	- the distros for picking up udev without me having to beg :)
	- everyone else who I know I've forgotten...

udev development isn't done, but for anyone who has not checked it out
yet, I suggest you do so.  I'll post a small HOWTO that shows how to
configure udev to manage your /dev without any problems or legacy issues
(the 2.4 kernel will still work just fine on the same box.)

If anyone has any suggestions for things that are lacking in udev,
please let me and the linux-hotplug-devel mailing list.  This especially
goes for any distro developers who are trying to integrate it into their
systems.

thanks again,

greg k-h

From: Greg KH [email blocked]
Subject: HOWTO use udev to manage /dev
Date: Thu, 19 Feb 2004 11:16:36 -0800


Here's a small document that I've added to the udev tarball that
explains how I managed to get udev to manage my /dev tree on a Red Hat
Fedora based machine.  All you Gentoo developers can just laugh as it's
already integrated into your distro.

Any users of other distros, feel free to send me updates to this to show
how to do it for yours.  Any distro maintainers, feel free to just
integrate udev into your system so this kind of tweaking isn't
necessary :)

thanks,

greg k-

---------------------------------------

HOWTO use udev to manage /dev

  This document describes one way to get udev working on a Fedora-development
  machine to manage /dev.  This procedure may be used to get udev to manage
  /dev on other distros, if you modify some of the steps.
  
  This will only work if you use a 2.6 based kernel, preferably the most
  recent one.  This does not prevent your machine from using a 2.4
  kernel, if you boot into one, udev will not run and your old /dev will
  be present with no changes needed.


NOTE NOTE NOTE NOTE NOTE NOTE NOTE
  This is completely unsupported.  Attempting to do this may cause your
  machine to be unable to boot properly.  USE AT YOUR OWN RISK.  Always
  have a rescue disk or CD handy to allow you to fix up any errors that
  may occur.
NOTE NOTE NOTE NOTE NOTE NOTE NOTE


 - Build and install udev as specified in the README that comes with
   udev.  I recommend using the following build options to get the
   smallest possible binaries:
	make USE_KLIBC=true USE_LOG=false DEBUG=false

 - disable udev from the boot process by running:
 	chkconfig udev off
   or
   	chkconfig --del udev
   as root.

 - place the start_udev script somewhere that is accessible by your
   initscripts.  I placed it into /etc/rc.d with the following command:
	copy extras/start_udev /etc/rc.d/
	
 - modify the rc.sysinit script to call the start_udev script as one of
   the first things that it does, but after /proc and /sys are mounted.
   I did this with the latest Fedora startup scripts with the patch at
   the end of this file.

 - make sure the /etc/udev/udev.conf file lists the udev_root as /dev.
   It should contain the following line in order to work properly.
	udev_root="/dev/"

 - reboot into a 2.6 kernel and watch udev create all of the initial
   device nodes in /dev


If anyone has any problems with this, please let me, and the
linux-hotplug-devel@lists.sourceforge.net mailing list know.

A big thanks go out to the Gentoo developers for showing me that this is
possible to do.

Greg Kroah-Hartman
<greg@kroah.com>


----------------------------------
Patch to modify rc.sysinit to call udev at the beginning of the boot
process:


--- /etc/rc.sysinit.orig	2004-02-17 11:45:17.000000000 -0800
+++ /etc/rc.sysinit	2004-02-17 13:28:33.000000000 -0800
@@ -32,6 +32,9 @@
 
 . /etc/init.d/functions
 
+# start udev to populate /dev
+/etc/rc.d/start_udev
+
 if [ "$HOSTTYPE" != "s390" -a "$HOSTTYPE" != "s390x" ]; then
   last=0
   for i in `LC_ALL=C grep '^[0-9].*respawn:/sbin/mingetty' /etc/inittab | sed 's/^.* tty\([0-9][0-9]*\).*/\1/g'`; do

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