DeviceKit is a simple system service that a) can enumerate devices; b) emits signals when devices are added removed; c) provides a way to merge device information / quirks onto devices. It is designed to partially replace hal and overcome some of the design limitiations of hal. DeviceKit functionality is provided in the form of dbus services on the system bus.
Apart from DeviceKit itself, there is DeviceKit-disks, which is a system service to keep track of block devices. The functionality offered by DeviceKit-disks is a superset of what hal provides for block devices.
There is also DeviceKit-power, which takes over the power-management-related parts of hal and the more complex functionality of gnome-power-manager. As a consequence, gnome-power-manager itself becomes much simpler.
The new udev-extra module will provide udev rules that are needed to make the DeviceKit architecture work. Functionality that was provided via .fdi files in hal will eventually be moved to udev rules, and setting acls on devices will also be done here at some point.
DeviceKit-disks comes with a graphical frontend called palimpsest. Furthermore, there will be a nautilus extension to format disks.
- Targeted release: Fedora 11
- Last updated: 2009-01-20
- Percentage of completion: 70%
DeviceKit, DeviceKit-disks, DeviceKit-power and gnome-disk-utility (i.e. palimpsest) packages have been built in rawhide.
gnome-power-manager 2.25.1 in rawhide uses DeviceKit-power instead of hal.
gvfs and gnome-mount have not yet been ported to DeviceKit-disks.
The nautilus extension for disk formatting is being worked on here.
David has written an extensive explanation of the DeviceKit architecture, and the motivation for rewriting hal. Read all about it here
There is a dedicated devkit-devel mailing list now.
Here are some screenshots of palimpsest in action:
Benefit to Fedora
Fedora gains a comprehensive graphical disk management tool which provides functionality that so far was almost exclusively available in the partitioning screen of anaconda. The tools integrate nicely into the desktop (by e.g. providing a "Format disk..." menuitem in the nautilus context menu where appropriate).
DeviceKit depends on bug fixes and enhancements in unreleased versions of a number of components, such as kernel, udev, mdadm, lvm. These will have to appear in rawhide first.
Also, in order to peacefully coexist with DeviceKit-disks, at a very minimum hal needs to talk to DeviceKit-disks about locking and mounting/unmounting. Medium term, hal functionality such as disk and power-management support will be turned off when all important users have been ported over to the equivalent DeviceKit api.
Core components that we want to have ported for F11 include gvfs, gnome-mount, nautilus and gnome-power-manager.
For completeness, here is a list of all packages in Fedora that depend on hal, libhal.so.1 or libhal-storage.so.1. Note that we don't expect to port most of these for F11.
- anaconda - will be ported when and if the installer team thinks that is a good idea
- bluez-gnome - only uses libhal to get the formfactor
- brasero - uses libhal to interact with drives
- cheese - uses libhal to find webcams
- concordance - only requires hal to install fdi files, should be fine
- conexusmm - uses libhal to find serial ports
- control-center - uses libhal in the sound capplet to find sound devices, will be solved by using the new sound capplet in gnome-media
- emelfm2 - uses libhal to find storage devices
- evolution - ipod plugin uses libhal to find ipod devices
- exo - uses libhal to find storage devices
- gdm - should be fine
- gimp - uses libhal to find input devices
- gnomad2 - uses libhal to find portable audio players
- gnome-device-manager - needs porting
- gnome-keyring - uses libhal to monitor removable storage devices
- gnome-mount - needs porting
- gnome-pilot - uses libhal to find usb devices
- gnome-power-manager - needs porting to DeviceKit-power
- gnome-utils - uses libhal to find floppy device
- gnome-vfs2 - needs porting
- gnome-volume-manager - uses libhal to handle volumes
- gparted - only requires hal to install fdi files, should be fine
- gstreamer-plugins-good - uses libhal to find audio devices
- gtkpod - uses libhal to find storage devices
- gvfs - needs porting
- gxine - uses libhal to find block devices
- hal-cups-utils - uses libhal to find printers
- halevt - needs porting
- hplip - requires hal to install fdi files, should be fine
- k3b - uses libhal to find cdrom devices
- kpowersave - should be ported to DeviceKit-power
- libfprint - installs a few fdi files, unused by any apps currently
- libipoddevice - uses libhal to find ipod devices
- libmtp - requires hal to install fdi files, should be fine
- libsynce - uses libhal to find pda devices
- nautilus-cd-burner - uses hal to interact with drives
- NetworkManager - uses libhal to find network devices
- nut - needs porting to DeviceKit-power
- odccm - uses libhal to find pda devices
- oxine - uses libhal to monitor volumes and drives
- pcmanfm - uses libhal to find volumes and drives
- pmount - uses hal to mount and unmount devices
- pm-utils - requires hal to install fdi files, should be fine
- pulseaudio - uses libhal to find audio devices
- python-minihallib - python wrapper around hal api
- rhpxl - uses hal to find mice and video cards
- rhythmbox - uses libhal to find remote audio players
- sane-backends - only requires hal to install an fdi file, should be fine
- synaptics - only requires hal to install an fdi file, should be fine
- thinkfinger - requires hal to install some fdi files, should be fine, and is obsoleted by fprintd anyway
- Thunar - uses libhal to monitor volumes and drives
- thunar-volman - uses libhal to monitor removable devices
- tracker - only uses libhal to track ac/battery status, should be ported to DK-power
- xfce4-volstatus-icon - uses libhal to monitor volumes and drives
- xorg-x11-server - uses libhal to find input devices
How To Test
- yum install gnome-disk-utility, this will pull in DeviceKit-disks and DeviceKit via dependencies.
- Use palimpsest (the graphical frontend) to create, modify and delete partitions and file systems on various media, such as usb sticks, cds, removable hard disks, etc.
- Use palimpsest to encrypt partitions and to change passwords for existing encrypted partitions.
- Verify that palimpsest correctly reports smart data from disks which support it.
- Test the raid support
- Test that desktop applications like nautilus and the gedit's file chooser see volumes and mounts
- Check that gnome-power-manager provides the same functionality it had in previous releases
- Similar for other desktop environments and applications, if they are ported to DeviceKit
There is a new menu item that brings up palimpsest: Applications → System Tools → Palimpsest Disk Utility
The nautilus context menu offers to format discs/usb sticks and other devices. palimpsest is a graphical interface for all disc-related tasks, from partitioning and file system creation to encryption, raid and lvm.
- DeviceKit review:
- DeviceKit-disks review:
- gnome-disk-utility review:
- DeviceKit-power review:
- udev >= 0.130
- udev-extra needs to be packaged.
- hal needs to be patched to remove block device handling.
- gvfs needs to be ported to DeviceKit-disks.
- gnome-mount and nautilus must be ported to DeviceKit-disks.
- a nautilus extension for formatting must be written.
DeviceKit-disks and DeviceKit-power can coexist with the disk and power management parts of hal. If the porting of applications is not complete by F11, we don't strip the functionality out of hal in F11.
End user documentation will take some time to write, and can't really be started before the tools are publicly available.
Fedora 11 features DeviceKit, which is a simpler, modular replacement for hal. hal itself is still around, since applications rely on it. DeviceKit also comes with a graphical disk management application called palimpsest that allows to handle partitioning, file system creation, encryption, raid, lvm, etc.