A device driver (sometimes called simply a driver) is a device-specific program that permits a computer's operating system to communicate with a particular hardware component or peripheral device such as a diskette drive, scanner, or printer. A device driver translates the input/output instructions of a computer's operating system to messages that the driver's specific device can understand. For example, a printer driver is a device driver that translates data into a language understood by a specific printer. The driver that works for one model of Epson printer, say, may not work for another Epson model, or for a Hewlett-Packard or Apple printer, because they all require slightly different instruction signals.

Programmers construct a driver to match each device's characteristics. This device driver software contains the instructions necessary to perform all functions requested by any computer application that may wish to activate the device in question...