Two by two: the story of the ARC

In the years immediately following the Second World War, there was much activity in both the USA and the UK to develop electronic computers. In this article, the author, then a Fellow at Birkbeck College London, recalls his own work to design a machine using relays-the automatic relay calculator (ARC). This was subsequently developed into a fully electronic computer APE(X)C, a version of which was sold by ICL. A key feature of these machines was the use of a magnetic drum store