Mechanical computation refers to the use of moving parts in a machine to perform mathematical operations upon numbers. The vast majority of modern computers perform their computations electronically, by manipulating the movement of electrons, and not through the movement of the parts of a machine. An example of the difference between the mechanical versus the electronic representation and manipulation of numbers is that of timekeeping devices. At one time, watches used springs, cogs, gears, etc. to "compute" and track time. Today, mechanical watches have largely been replaced by electronic versions in which no moving parts are used.

One of the first devices used for mechanical computations was the abacus. Abacuses, which are still used in some parts of the world today, usually consist of a rectangular frame enclosing rods on which balls or beads are moved. A person moves the beads to perform arithmetic calculations. Versions...