The concept of building a computer using an array of processors came to Daniel Slotnick while working as a programmer on the IAS machine in 1952. A formal design did not start until 1960, when Slotnick was working at Westinghouse Electric and arranged development funding under a US Air Force contract. When that funding ended in 1964, Slotnick moved to the University of Illinois and joined the Illinois Automatic Computer (ILLIAC) team. With funding from Advanced Research Projects Agency (ARPA), they began the design of a newer concept with 256 64-bit processors instead of the original concept with 1,024 1-bit processors.