Maurice Wilkes - Other Computing Developments

Other Computing Developments

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 Manchester University Computer Inaugural Conference in 1951, then published in expanded form 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. 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 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 systems (now termed a multi-user operating system) and distributed computing. Toward the end of the 1960s, Wilkes also became interested in capability-based computing, and the laboratory assembled a unique computer, the Cambridge CAP.

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 England.