bus

The communication path used between the component parts of a computer.

In computing, the electrical pathway through which a computer processor communicates with some of its parts and/or peripherals. Physically, a bus is a set of parallel tracks that can carry digital signals; it may take the form of copper tracks laid down on the computer's printed circuit boards (PCBs), or of an external cable or connection.

A computer typically has three internal buses laid down on its main circuit board: a data bus, which carries data between the components of the computer; an address bus, which selects the route to be followed by any particular data item travelling along the data bus; and a control bus, which is used to decide whether data is written to or read from the data bus. An external expansion bus is used for linking the computer processor to peripheral devices, such as modems and printers.

bus

Vehicle that carries fare-paying passengers on a fixed route, with frequent stops where passengers can get on and off.

An omnibus appeared briefly on the streets of Paris in the 1660s, when the mathematician Blaise Pascal introduced the first horse-drawn vehicles for public use. But a successful service, again in Paris, was not established until 1827. In 1829 George Shillibeer introduced a horse-drawn bus in London.

Gasoline-engine buses came into general use by the 1910s and provide intracity and nationwide service through both public and private companies. A hydrogen-powered bus began operating in Augusta, Georgia, in 1997.