Heaviest portable computer

The heaviest portable computer was DYSEAC, a first-generation vacuum-tube computer built by the US Government's National Bureau of Standards in Gaithersburg, Maryland. DYSEAC, which was made for the US Department of Defense and completed in May 1954, comprised two customized 40-foot (12.1-m) trailers: one held the DYSEAC computer, the other a bank of power supplies, air conditioning units and auxiliary equipment space. The computer trailer weighed 12 US tons (10,886 kg) and the support trailer weighed 8 US tons (7,257 kg) for a total mass of 20 US tons (18,143 kg).

In the early 1950s, the department of defense had researchers working in facilities scattered all over the US, and at the time it wasn't practical for each to have its own computer installed. The idea behind DYSEAC was to have a mobile computing team who could travel to different locations to assist with projects as needed. The computer's first operational role was calculating ballistics data at the White Sands Missile Range in New Mexico. To assist with its planned role, the computer was made to be as flexible as possible, and able to accept a wide variety of input formats. The auxiliary space in the second trailer was intended to house additional peripherals or interfaces.