1. A routine within an operating system that handles the individual peripheral units on the computer system. Of necessity a driver routine is required to deal with the intimate details of the construction of each unit and of its real-time behaviour. Consequently at least some of the driver will often need to be written in a machine-oriented programming language.

2. An electronic circuit, often available in the form of a logic gate, that is capable of providing large currents or voltages to other circuits connected to the driver’s output. These devices are often used to place signals onto bus lines, hence the term bus driver.