Between 1937 and 1970, computers were difficult to make, difficult to keep running and difficult to use. Since 1970, everything has become progressively easier. Today every academic has at least one computer on his or her desk, and the Computing Service has changed greatly as a result. In 1937 the remit of the Mathematical Laboratory at Cambridge included the requirement to provide a computing service for general use, and to be a centre for the development of computational techniques in the University. But computers as we now know them did not exist at that time. The EDSAC, developed by the Computing Service at Cambridge, was the world's first stored-program computer which successfully executed its first program in May 1949.