Program (machine)

A program is a set of instructions used to control the behavior of a machine, often a computer (in this case it is known as a computer program).

Examples of programs include:

• The sequence of cards used by a Jacquard loom to produce a given pattern within weaved cloth. Invented in 1801, it used holes in punched cards to represent sewing loom arm movements in order to generate decorative patterns automatically.

• A computer program list of instructions to be executed by a computer.

• Barrels, punched cards and music rolls encoding music to be played by player pianos, fairground organs, barrel organs and music boxes.

The execution of a program is a series of actions following the instructions it contains. Each instruction produces effects that alter the state of the machine according to its predefined meaning.

While some machines are called programmable, for example a programmable thermostat or a musical synthesizer, they are in fact just devices which allow their users to select among a fixed set of a variety of options, rather than being controlled by programs written in a language (be it textual, visual or otherwise).