Software to control a hardware component or peripheral device of a computer such as a magnetic disk, magnetic tape or printer.

A device driver is responsible for accessing the hardware registers of the device and often includes an interrupt handler to service interrupts generated by the device.

Device drivers often form part of the lowest level of the operating system kernel, with which they are linked when the kernel is built. Some more recent systems have loadable device drivers which can be installed from files after the operating system is running.