LEO and its Applications: The Beginning of Business Computing

Fifty years have passed since a visit to the United States set in train the building in Britain of the world’s first business computer. The computer was built by J. Lyons & Co., then Britain’s leading caterer with a household name for its teashops, its packeted tea and its cakes and ice cream. The system was given the name LEO, Lyons Electronic Office, and on it was run the world’s first regular, routine computer office application. What follows is an account of how LEO came to be built by seemingly the unlikeliest of organizations and how it was put to work. After the pioneering system, later to be known as LEO I, there came more advanced models exploiting the rapid technological developments of the time and the operational experience that had been gained. These were put to work by leading industrial, commercial and governmental organizations both at home and abroad. There was a succession of applications that kept the name, LEO, prominent in the computer world for 20 years. Eventually, though it was overcome by the sheer weight of resources that became indispensable to manufacturers as the technology raced ahead. The engineering aspects of the innovation have already been fully covered by the lucid exposition by Dr John Pinkerton in Electronic Engineering [1]. Less attention has been paid in the past to the application aspects. Those are the principal concern of this paper: how they were defined, what was necessary to enable them to run economically on LEO, and what techniques were used to keep them running accurately and on time on a system that was inevitably less reliable than those to which present-day computer users are accustomed. In this paper there are five main sections. The first describes the genesis of the LEO idea and the second traces how it was brought to fruition on the foundation of EDSAC at Cambridge. The third section sketches early applications before the LEO system was fully equipped for business applications, and the fourth the major applications that followed. Finally, there is a review of what was achieved and of the construction of a successor system. 2. GENESIS