Maurice Vincent Wilkes

British computer scientist

• Born: June 26, 1913; Dudley, England
• Died: November 29, 2010; Cambridge, England

Maurice Wilkes designed and built the EDSAC computer, the first computer to combine mercury delay line memory with stored program instructions. He later developed WISP, one of the first high-level programming languages.

Primary field: Computer science

Specialties: Logic; information theory; electromagnetism; atmospheric sciences

Early Life

Maurice Vincent Wilkes was born in the village of Dudley in Worcestershire, England, on June 26, 1913. His father worked as a clerk on the estates of the Earl of Dudley. One of his father’s duties was to operate the private telephone switchboard, which at the time was considered advanced technology. Perhaps in consequence, Wilkes’s childhood interests were mechanical toys, batteries, lights, and buzzers.

Wilkes attended the King Edward VI Grammar School in Stourbridge. After completing the junior course, he was promoted to the main school, where he began a four-year syllabus emphasizing mathematics and science, in addition to English and modern languages. As a young student, Wilkes became interested in radio and built several receivers. One of his teachers, the chemist J. Timbrell, was also a radio enthusiast and encouraged him to study for an amateur radio transmitting license. Wilkes succeeded and later built his own transmitting equipment.

In 1931, Wilkes applied to Cambridge University and was accepted. At Cambridge, Wilkes studied mathematics for three years while maintaining his interest in amateur radio. He graduated with first-class honors in June 1934.

As a result of his strong showing in his degree examinations, Wilkes received a research grant that allowed him to study the propagation of radio waves at the university’s Cavendish Laboratory. The work combined his interest in mathematics with practical radio applications. In March 1936, while Wilkes was pursuing this research, he received a demonstration of a mechanical differential analyzer that had been using pieces of a metallic toy. This machine, which could produce analog solutions of simple differential equations, fascinated Wilkes. Its success resulted in a proposal to establish a mathematical laboratory at Cambridge. Wilkes accepted a post in the new laboratory in 1938.

Life’s Work

Wilkes was working in Cambridge in September 1939, when World War II started. He had earned his PhD in October 1938 after presenting a thesis on long-wave radio propagation. Wilkes and many of his colleagues worked in support of the war effort after Britain declared war on Germany. Wilkes worked on developing radar technology. When the war broke out, Britain already had some radar apparatus in service. It used a wavelength of 1.5 meters. In radar, the shorter the wavelength the more precise the results. Wilkes was part of a group that developed and built radar sets with a wavelength of 50 centimeters. Later in the war, they successfully built sets of 10- and 3-centimeter wavelengths. The resolution of the latter equipment was so fine that shell splashes in the water could be detected, thus making the equipment suitable for controlling naval gunnery. Beginning in 1943, Wilkes also worked on “operations research”—the application of mathematical statistics or game theory to practical military operations.

After World War II ended, Wilkes became interested in atmospheric oscillations. These oscillations occur as the result of tidal forces working on the atmosphere with the rise and fall of the moon. The necessary mathematical analyses required immense amounts of computation, far beyond any practical production with mechanical adding machines. This need spurred Wilkes to return to his earlier interest in the differential analyzer and other new forms of calculating machinery. In 1946, he read John von Neumann’s famous 1945 paper “First Draft of a Report on the EDVAC,” on the Electronic Discrete Variable Automatic Computer being developed in the United States. This paper set out the principles on which digital computers could be constructed. Wilkes later wrote, “I recognized this at once as the real thing, and from that time on never had any doubt as to the way computer development would go.”

The Moore School of Electrical Engineering at the University of Pennsylvania in Philadelphia invited Wilkes to attend a course in electronic computers. Wilkes leaped at the opportunity, and sailed for the United States in August 1946. While in the United States, he met von Neumann and other American computer scientists and discussed computer architecture with them. While in Boston in September 1946, he began to sketch out the design of the machine that became EDSAC—the Electronic Delay Storage Automatic Calculator. Upon his return to England, Wilkes set to work on building EDSAC with his team at the Cambridge University Mathematical Laboratory. Mercury delay lines were used as the machine’s memory. Upon its completion in 1949, EDSAC was more advanced than its two giant American predecessors, ENIAC and EDVAC.

Once EDSAC was completed, Wilkes turned his attention to programming issues. He had come to believe that subroutines—subordinate computer programs completing discrete tasks within a larger program—could be developed for the use of the main computer program. Within two years, a library of subroutines for EDSAC had been written, which permitted the laboratory to solve complex problems in many disciplines. For example, Wilkes himself worked with the biologist Ronald Fisher to write a routine that solved an equation for Fisher’s paper on gene frequencies. This effort represented the first application of computer technology to the science of biology.

Wilkes realized that general-purpose computer languages would be necessary, and some of his laboratory’s staff set to work on devising them. Wilkes himself devised a programming language called WISP. This was a list processor, and was in vogue as a teaching tool for some time. It also had some practical applications.

When work surrounding the development of EDSAC became routine, Wilkes began work on a successor machine, EDSAC 2. This machine, more advanced than EDSAC, was used for production computing until 1956.

Repeatedly over the course of his career in computing, Wilkes visited the United States in order to keep up with American technological developments. Following his retirement from Cambridge University, he and his family moved to the United States, where he took up a post as a senior engineer and consultant on the staff of Digital Equipment Corporation (DEC), a large American computer firm. In 2002, he moved back to Cambridge.

Wilkes received many university and organizational honors in his lifetime, including an honorary doctor of science degree from Cambridge University. He was knighted in the 2000 New Year Honors List. Wilkes died on November 29, 2010, at the age of 97.

Impact

Wilkes lived to see his systems of computer architecture and programming widely implemented. Computer programs are written using Boolean logic, and all but the simplest use subroutines. These characteristics are all consistent with the architecture that Wilkes helped devise. Indeed, the extraordinary capabilities of solid state electronics—central processing units with billions of transistors and dynamic random access memories in the range of gigabytes—are proof of how sound Wilkes’s architecture actually is. Any number of alternate designs could have supplanted those of Wilkes in the half-century that followed his work, but none have proven to be more effective, and, as Wilkes foresaw, computers have in that time become ubiquitous.

Bibliography

Campbell-Kelly, Martin, and William Aspray. Computer: A History of the Information Machine, 2nd ed. Boulder, CO: Westview, 2004. Print. Traces the development of computing machinery from Charles Babbage to the present. Includes a discussion on the designs of ENIAC and EDVAC.

Goldstine, Herman H. The Computer from Pascal to von Neumann. Princeton: Princeton UP, 1980. Print. Covers the development of computers as both historian and participant. Maurice Wilkes’s role is frequently discussed.

Wilkes, Maurice V. Memoirs of a Computer Pioneer. Cambridge, MA: MIT Press, 1985. Wilkes recounts his life and work. Includes a discussion of his associates and collaborates, and his other scientific interests.