Overview
All devices, such as printers, terminals, and CD-ROMs, are connected to your Linux operating system through special files called device files. Such a file contains all the information your operating system needs to control the specified device. This design introduces great flexibility. The operating system is independent of the specific details for managing a particular device; the specifics are all handled by the device file. The operating system simply informs the device what task it is to perform, and the device file tells it how. If you change devices, you have to change only the device file, not the whole system.
To install a device on your Linux system, you need a device file for it, software configuration such as that provided by a configuration tool, and kernel support—usually supplied by a module or support that is already compiled and built into the kernel. An extensive number of device files are already set up for different kinds of devices. Usually you need only one, which is specific to your device. When you add new hardware devices, Kudzu, the Red Hat hardware probing tool, checks for the new hardware when your system boots. The Kudzu tool automatically detects a new device and lets you configure it. A profile of your hardware configurations is saved by Kudzu in the /etc/sysconfig/hwconf file. For more specialized kernel support, you may have to load a kernel module or recompile the kernel, both simple procedures (see Chapter 33). In most cases, support is already built into the kernel.
