An EDSAC (Electronic Delay Storage Automatic Calculator)

It was "developed by a group of scientists, headed by Professor Maurice Wilkes at Cambridge University, England, in 1949. It was also based on the stored program concept and one of the first to use binary digits. The input and output were provided by a paper tape. It could do about 700 additions per second and 200 multiplications per second. The machine occupied a room, which measured 5/4 meters."