An abstract form of a computing device that is more like a
software program than a piece of hardware. Any so-called Turing machine can be
implemented on an infinite number of computing devices. A Turing machine would
have a read/write head that scans a one-dimensional, bidirectional tape divided
into equal-sized sections inscribed with a 1 or a 0. Computation starts when
the mechanism in a given Â“stateÂ” scans a section, erasing what it discovers
there, printing a 0 or a 1, moving to an adjacent section, and going into a new
This behavior is determined by three key parameters: (1) the
state the mechanism is in; (2) the value in the section the mechanism is
scanning; and (3) a set of instructions. For decades, a number of computer scientists have proven that if
conventional digital computers are considered in isolation from random external
inputs (for example, a stream of bits produced by radioactive decay), then with
enough time and tape, a Turing machine could calculate any function a digital
computer could calculate.
Stanford Encyclopedia of Philosophy. Turing Machine. [Online, May 27, 2003.]
Stanford Encyclopedia of Philosophy Website.
machine/; Computing Corporation Website.