The world’s first stored-program electronic digital computer successfully executed its first program on 21st June 1948. That program was written by Tom Kilburn who, along with the late F.C. (Freddie) Williams designed and built the machine. It was called the “Small Scale Experimental Machine”, but was soon nicknamed the “Baby”. It is also sometimes known as the Mark 1 prototype. In modern terms the prototype Baby had a RAM (random access memory) of just 32 locations or ‘words’. Each word in the RAM consisted of 32 bits (binary digits) and so The Baby had a grand total of 1024 bits of memory – and a computing speed of 1.2 milliseconds per instruction. And amazingly, today a pocket-sized 80 GB Apple iPod is capable of storing 640 MILLION times more information than the original room-sized Baby. Compared with today’s computers, Baby was a dinosaur, with less computing power than a modern calculator.
The Baby weighing about one-ton was built using metal Post Office racks, hundreds of valves or vacuum tubes and the keyboard was a series of push buttons and switches, mounted vertically. Instead of a screen, the output was read directly off the face of a Cathode Ray Tube (CRT). In 1951, Baby was dismantled to make way for bigger and better models. However, a working replica is on display at the Museum of Science and Industry in Manchester.
