The Mark I Computer, also known as the Harvard Mark I, was one of the first electromechanical computers, developed during World War II. Completed in 1944, it was designed by Howard Aiken and built by IBM. The machine was about 51 feet long and used over 750,000 components, including switches and relays, to perform calculations. The Mark I could execute basic arithmetic operations and was capable of handling complex calculations automatically. It operated using punched tape for input and produced results on paper. Although it was not a fully electronic computer, the Mark I laid the groundwork for future computing advancements.