Modern computers
The principle of the modern computer was proposed by Alan Turing in his seminal 1936 paper, On Computable Numbers. Turing proposed a simple device that he called "Universal Computing machine" and that is now known as a universal Turing machine.
He proved that such a machine is capable of computing anything that is
computable by executing instructions (program) stored on tape, allowing
the machine to be programmable. The fundamental concept of Turing's
design is the stored program, where all the instructions for computing are stored in memory.The central concept of the modern computer was due to this paper was acknowledged by Von Neumann.This day Turing machines are to a central object of study in theory of computation. Except for the limitations imposed by their finite memory stores, modern computers are said to be Turing-complete, which is to say, they have algorithm execution capability equivalent to a universal Turing machine.
Stored programs
Earliest computing machines had fixed programs. Changing function required the re-wiring and re-structuring of the machine.With the proposal of the stored-program computer this changed. A stored-program computer includes by design an instruction set and can store in memory a set of instructions (a program) that details the computation. The theoretical basis for the stored-program computer was laid by Alan Turing in his 1936 paper. In 1945 Turing joined the National Physical Laboratory
and began work on developing an electronic stored-program digital
computer. His 1945 report "Proposed Electronic Calculator" was the first
specification for such a device. John von Neumann at the University of Pennsylvania also circulated his First Draft of a Report on the EDVAC in 1945.
The Manchester Small-Scale Experimental Machine(MSSEM), called Baby, was the world's first stored-program computer. It was built at the Victoria University of Manchester by Frederic C. Williams, Tom Kilburn and Geoff Tootill, and ran its first program on 21 June 1948.It was designed as a testbed for the Williams tube, the first random-access digital storage device.Although the computer was considered "small and primitive" by the
standards of its time, it was the first working machine to contain all
of the elements essential to a modern electronic computer.
As soon as the SSEM had demonstrated the feasibility of its design, a
project was initiated at the university to develop it into a more usable
computer, the Manchester Mark 1.
The Mark 1 in turn quickly became the prototype for the Ferranti Mark 1, the world's first commercially available general-purpose computer. Built by Ferranti, it was delivered to the University of Manchester in February 1951. At least seven of these later machines were delivered between 1953 and 1957, one of them to Shell labs in Amsterdam.In October 1947, the directors of British catering company J. Lyons & Company decided to take an active role in promoting the commercial development of computers. The LEO I computer became operational in April 1951and ran the world's first regular routine office computer job.
No comments:
Post a Comment