Turing's World

Turing's World simulates the workings of a Turing machine. A Turing machine is a very primitive "computer," which uses an infinitely long "tape" for all its input, output, and storage needs. Although very simple, Turing machines are in principle capable of computing anything that can be computed, and hence are of great interest in the theory of computability. Turing's World allows the student to specify Turing machine programs for the machine to execute. The student enters a program by building a state diagram, which can subsequently be executed, debugged, and edited. Other major features include cutting, copying, and pasting of Turing submachines, various modes of execution, a "time-space complexity counter," and user-specifiable alphabets.

Turing's World is intended for students taking a first course in computability theory. Turing's World is helpful for these students in a variety of ways: (1) by interactively entering, executing, and debugging Turing machine programs, they can gain a better understanding of Turing machines--the ability to enter programs via state diagrams instead of the more formal, less easily understood "4-tuples" also aids this process; (2) the time-space complexity counter is useful for illustrating complexity theory; and (3) the ability to specify submachines, and to easily duplicate them and use them elsewhere, allows the program to be used for illustrating the equivalence of Turing machines to other forms of automata .