Maurice Wilkes

Wilkes was born in Dudley, Worcestershire, England the only child of Ellen (Helen), née Malone (1885–1968) and Vincent Joseph Wilkes (1887–1971), an accounts clerk at the estate of the Earl of Dudley.

He grew up in Stourbridge, West Midlands, and was educated at King Edward VI College, Stourbridge.

During his school years he was introduced to amateur radio by his chemistry teacher.

Sir Maurice Vincent Wilkes (26 June 1913 – 29 November 2010) was an English computer scientist who designed and helped build the Electronic Delay Storage Automatic Calculator (EDSAC), one of the earliest stored program computers, and who invented microprogramming, a method for using stored-program logic to operate the control unit of a central processing unit's circuits.

At the time of his death, Wilkes was an Emeritus Professor at the University of Cambridge.

He studied the Mathematical Tripos at St John's College, Cambridge, from 1931 to 1934, and in 1936 completed his PhD in physics on the subject of radio propagation of very long radio waves in the ionosphere.

He was appointed to a junior faculty position of the University of Cambridge, through which he was involved in the establishment of a computing laboratory.

He was called up for military service during World War II and worked on radar at the Telecommunications Research Establishment (TRE) and in operational research.

In 1945, Wilkes was appointed as the second director of the University of Cambridge Mathematical Laboratory (later known as the Computer Laboratory).

The Cambridge laboratory initially had many different computing devices, including a differential analyser.

One day Leslie Comrie visited Wilkes and lent him a copy of John von Neumann's prepress description of the EDVAC, a successor to the ENIAC under construction by Presper Eckert and John Mauchly at the Moore School of Electrical Engineering.

He had to read it overnight because he had to return it and no photocopying facilities existed.

He decided immediately that the document described the logical design of future computing machines, and that he wanted to be involved in the design and construction of such machines.

In August 1946 Wilkes travelled by ship to the United States to enroll in the Moore School Lectures, of which he was only able to attend the final two weeks because of various travel delays.

During the five-day return voyage to England, Wilkes sketched out in some detail the logical structure of the machine which would become EDSAC.

Since his laboratory had its own funding, he was immediately able to start work on a small practical machine, EDSAC (for "Electronic Delay Storage Automatic Calculator"), once back at Cambridge.

He decided that his mandate was not to invent a better computer, but simply to make one available to the university.

Therefore, his approach was relentlessly practical.

He used only proven methods for constructing each part of the computer.

The resulting computer was slower and smaller than other planned contemporary computers.

However, his laboratory's computer was the second practical stored-program computer to be completed and operated successfully from May 1949, well over a year before the much larger and more complex EDVAC.

In 1950, along with David Wheeler, Wilkes used EDSAC to solve a differential equation relating to gene frequencies in a paper by Ronald Fisher.

This represents the first use of a computer for a problem in the field of biology.

In 1951, he developed the concept of microprogramming from the realisation that the central processing unit of a computer could be controlled by a miniature, highly specialised computer program in high-speed ROM.

This concept greatly simplified CPU development.

Microprogramming was first described at the University of Manchester Computer Inaugural Conference in 1951, then expanded and published in IEEE Spectrum in 1955.

This concept was implemented for the first time in EDSAC 2, which also used multiple identical "bit slices" to simplify design.

Interchangeable, replaceable tube assemblies were used for each bit of the processor.

Toward the end of the 1960s, Wilkes also became interested in capability-based computing, and the laboratory assembled a unique computer, the Cambridge CAP.

The next computer for his laboratory was the Titan, a joint venture with Ferranti Ltd begun in 1963.

It eventually supported the UK's first time-sharing system which was inspired by CTSS and provided wider access to computing resources in the university, including time-shared graphics systems for mechanical CAD.

A notable design feature of the Titan's operating system was that it provided controlled access based on the identity of the program, as well as or instead of, the identity of the user.

It introduced the password encryption system used later by Unix.

Its programming system also had an early version control system.

Wilkes is also credited with the idea of symbolic labels, macros and subroutine libraries.

These are fundamental developments that made programming much easier and paved the way for high-level programming languages.

Later, Wilkes worked on an early timesharing system (now termed a multi-user operating system) and distributed computing.

In 1974, Wilkes encountered a Swiss data network (at Hasler AG) that used a ring topology to allocate time on the network.

The laboratory initially used a prototype to share peripherals.

Eventually, commercial partnerships were formed, and similar technology became widely available in the UK.