Designers have long used computers for their calculations. Digital computers were used in power system analysis or optimization as early as proto-" Whirlwind " in 1949 . Circuit design theory, or power network methodology would be algebraic , symbolic , and often vector -based. Examples of problems being solved in the mid-1940s to 50s include, Servo motors controlled by generated pulse (1949), The digital computer with built-in compute operations to automatically co-ordinate transforms to compute radar related vectors (1951) and the essentially graphic mathematical process of forming a shape with a digital machine tool (1952). These were accomplished with the use of computer software. The man credited with coining the term CAD. Douglas T. Ross stated "As soon as I saw the interactive display equipment, [being used by radar operators 1953]. The designers of these very early computers built utility...