Von Neumann's 'First Draft of a Report on the EDVAC', completed in the spring of 1945, also set out a design for an electronic stored-program digital computer ('EDVAC' stood for 'Electronic Discrete Variable Computer').Von Neumann's report, to which Turing referred in 'Proposed Electronic Calculator', was more abstract than Turing's, saying little about programming or electronics.By the end of 1945, thanks to wartime developments in digital electronics, groups in Britain and in the United States had embarked on creating a universal Turing machine in hardware.Turing headed a group situated at the National Physical Laboratory (NPL) in Teddington, London.There is a happy ending—but by that time Turing had turned his back on the ACE forever.

He gave the following simple example.7 A machine—call it M—begins work with an endless blank tape and with the scanner positioned over any square of the tape.The basic principle of the modern computer—the idea of controlling the machine's operations by means of a program of coded instructions stored in the computer's memory—was conceived by Alan Turing.Turing's abstract 'universal computing machine' of 1936, soon known simply as the universal Turing machine, consists of a limitless memory, in which both data and instructions are stored, and a scanner that moves back and forth through the memory, symbol by symbol, reading what it finds and writing further symbols.2 By inserting different programs into the memory, the machine is made to carry out different computations.The scanner moves back and forth through the memory, examining one square at a time (the 'scanned square').It reads the symbols on the tape and writes further symbols.