At the end of September 1972, the University of London ATLAS 1 Computer was taken out of service to be sold for scrap. This was rather a sad occasion for all those who had operated and used ATLAS, but this day also marked the end of the ATLAS era, the beginning of which made a very important impact on the computing world, which impact is still important today.
The ATLAS computer was the result of many years of cooperation between the University of Manchester and Ferranti Limited. This co-operation was begun with the Manchester Universal Computer marketed by Ferranti as the Ferranti Mark 1 Electronic Digital Computer. This machine was built on a design developed by Professor Williams and Professor Kilburn at Manchester, and used cathode ray tubes for high speed storage backed by a magnetic drum store. The Ferranti Mercury Computer was also developed jointly with the University of Manchester. Mercury was, in its time, a highly advanced computer having both drum and magnetic core stores.
ATLAS must be seen as an example of very deep collaboration between industry and an academic institution, the resulting design being extremely advanced and sophisticated.
The ideas pioneered in ATLAS included the one-level store, extracodes, a rudimentary instruction pipeline and a very sophisticated operating system (known as the Supervisor), which drove the system with a minimum of human intervention.
This book is divided into two basic parts: the first part gives a potted history of the early days of the ATLAS at the University of London and the second outlines, in an informal way, some of the distinctive features of the ATLAS computer system.
