RHEL udev

Hotplugging (which is the word used to describe the process of inserting devices into a running system) is achieved in a Linux distribution by a combination of three components: Udev, HAL, and Dbus.

Udev^[1] supplies a dynamic device directory containing only the nodes for devices which are connected to the system. It creates or removes the device node files in the /dev directory as they are plugged in or taken out. Dbus is like a system bus which is used for inter-process communication. The HAL gets information from the Udev service, when a device is attached to the system and it creates an XML representation of that device. It then notifies the corresponding desktop application like Nautilus through the Dbus and Nautilus will open the mounted device‚