When the Mark I was assembled at Harvard in 1944, a handful of Harvard civilians ran the first series of test problems, becoming its first operators. In the following months the Navy completed the crew with its own personnel to apply the computer’s powers to wartime problems. The machine’s inventor, Howard Aiken, who had enlisted in the Navy in 1941, was put back in charge with the rank of commander. A cadre of officers with advanced mathematical training, directed by two mathematics PhDs, programmed the machine. A group of enlisted men working around the clock in 8-hour shifts rounded out the team. These groups—the Harvard civilians, Navy officers, and enlisted men—formed the core team who had the monumental task of turning diverse mathematical problems into actual numerical results from a new machine about which most of them knew little.
The biggest hurdle was to translate mathematical problems into a set of clearly defined steps the machine could understand. This involved designing sequential instructions, strings of numbers, and custom wirings. The team referred to this process as the “coding” of a problem.
The coding pioneers of wartime Mark I went on to prominent positions in the computer industry of the postwar years.