1.3.1.2 Modular hardware driver

The kernel of an operating system is specific only to the processor of a computer and some of the other core components (such as memory and sometimes chipset). It does not include components to utilize I/O peripherals.

Software that interface the kernel of an operating system to I/O peripheral devices consists of device drivers. Device drivers are dependent on the periperals installed in a PC. Some common and basic device drivers are often ``bundled'' with an operating system to provide very basic services. Such device drivers include the drivers of the ATA bus, ATA hard disks, optical disks, basic video controllers and basic sound controllers.

Because the developer (and distributor) of an operating system cannot predict and account for all the possible peripherals that are and will be available, it is up to peripheral vendors to supply device drivers for their own products. Such devices drivers must be installed before the hardware devices can be used.