Relationship between udev, hal, Dbus and DeviceKit?

[Noe Misael]

All right,

Thanks a lot, that clarifies everything!!

I read that Ubuntu 10.04 will ship without HAL. I was not completely shure
why udev+dbus was better. Now I see.


Regards.

---Noe Nieto



2010/4/25 Lennart Poettering <mzqohf at 0pointer.de>

> On Sun, 25.04.10 19:49, Noe Misael (tzicatl at gmail.com) wrote:
>
> > Hi.
> >
> > I'm trying to understand how modern linux systems handle hardware
> devices. I
> > have a general idea about how kernel drivers works and also have a
> general
> > idea about how udev is a layer between the kernel and user-space.
> >
> > But when looking at HAL and Dbus, DeviceKit, Network Manager I started to
> > get confused.
> >
> > Can anyone be so kind to explain me how are these software components
> > interacting with each other?
>
> Ignore devicekit. I doesn't exist, it never really came to be.
>
> Ignore HAL, too, as it is obsolete and only used by legacy code.
>
> udev provides low-level access to the linux device tree. Allows programs
> to enumerate devices and their properties and get notifications when
> devices come and go.
>
> dbus is a framework to allow programs to communicate with each other,
> securely, reliably, and with a high-level object-oriented programming
> interface.
>
> udisks (formerly known as DeviceKit-disks) is a daemon that sits on top
> of libudev and other kernel interfaces and provides a high-level
> interface to storage devices and is accessible via dbus to applications.
>
> upower (formerly known as DeviceKit-power) is a daemon that sits on top
> of libudev and other kernel interfaces and provides a high-level
> interface to power management and is accessible via dbus to apps.
>
> NetworkManager is a daemon that sits on top of libudev and other kernel
> interfaces (and a couple of other daemons) and provides a high-level
> interface to network configuration and setup and is accessible via dbus
> to apps.
>
> (hal was a lot of this all mingled in one big daemon, and eventually
> proved to suck in its design)
>
> Of course, NM should probably be renamed to "unetwork", and dbus to
> "ubus". And PulseAudio to "usound", and X11 to "udisplay", and then
> undescribable happiness would come down to all people of this world.
>
> Lennart
>
> --
> Lennart Poettering                        Red Hat, Inc.
> lennart [at] poettering [dot] net
> http://0pointer.net/lennart/           GnuPG 0x1A015CC4
>
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