D-BUS, anyone?

[Rob Andrews]

On 05-Dec-2005 07:33.48 (GMT), Rahul Siddharthan wrote:
 > I've been very impressed with linux lately: I installed ubuntu 5.10
 > on my wife's laptop, and if you insert a CD or a memory stick or
 > a digital camera or whatever, it "just works" -- an icon pops up on 
 > the desktop and you can look at the contents, drag and drop etc
 > (with either gnome or KDE).  This sort of thing is really needed for
 > non-techie users, but even I find it pretty convenient.
 > 
 > As I understand, it works with dbus and hal
 >    http://www.freedesktop.org/Software/hal
 > and hal, at least, requires kernel support: it seems to work only with
 > linux kernel 2.6, not 2.4.

The automounting is udev[0] (a userspace device filesystem that is
triggered[1] by the kernel when a hardware event occurs), which creates a
device node and triggers hal to do the rest of the job. As I understand it,
hal does the job of putting the message onto the dbus which in turn means
anything listening to the dbus (gnome-volume-manager which automounts in
this case) can perform any necessary duties.

In my understanding of MacOS 10 this is mostly how it goes about it's
business of automounting.

Other examples of where dbus is used these days include Evolution - it
can create a dbus message when new mail arrives, and bluez-utils can
perform bluetooth pin exchange over dbus when a device initiates pairing
with a host.

[0] used to be a pair of tools, 'hotplug' and 'udev', the former was a
    dependancy of the latter but as I gather they have been rolled into
    one.

[1] the hotplug handler is set in /proc/sys/kernel/hotplug, or sysctl
    kernel.hotplug in bsd speak <g>

-- 
rob andrews                                            rob at xxxxxxxxxxxxx