The baby is actually called the manchester baby or the small scale experimental machine or SSEM and was the first “modern computer” even though it looked nothing like one, It was 17 feet (5.2 m) in length, 7 feet 4 inches (2.24 m) tall, and weighed almost 1 long ton (1.0 t). The machine contained 550 valves, and had a power consumption of 3500 watts.The arithmetic unit was built using EF50 pentode valves, which had been widely used during wartime.. the value of the most significant bit denotes the sign of a number; positive numbers have a zero in that position and negative numbers had one. the range of numbers that could be held in each 32-bit word was −231 to +231. the baby was made its frist test run on june 21, 1948