John Vincent Atanasoff, an engineer at Iowa State University, built a full-scale model of his computer, using 300 vacuum tubes. His computer, however, received little attention, and his patent was not applied for by his legal department. The computer’s limitations, however, were that despite the extremely fast calculations performed with vacuum tubes, memory access was slow due to rotating disks, and writing to memory, burning holes on punched cards, was also slow.
