The ILLIAC I (Illinois Automatic Computer), a pioneering computer built in 1952 by the University of Illinois, was the first computer built and owned entirely by an educational institution.

ILLIAC I was based on the Institute for Advanced Study (IAS) Von Neumann Architecture edited by mathematician John von Neumann. Unlike other computers of its era, the ILLIAC I and ORDVAC computers were twin copies of the same design, and so therefore they could exchange software. The computer had 2,800 vacuum tubes, measured 10 ft (3 m) by 2 ft (0.6 m) by 8½ ft (2.6 m) (L×B×H), and weighed 5 tons (4.5 t). ILLIAC I was very powerful for its time; in 1956 it had more computing power than all of Bell Labs.

Because the lifetime of the tubes within ILLIAC was about a year, the machine was shut down every day for "preventive maintenance" when older vacuum tubes would be replaced in order to increase reliability. The machine was retired in 1962, when the ILLIAC II became operational.

Innovations

• 1955, Lejaren Hiller and Leonard Isaacson, used ILLIAC I to compose the "Illiac Suite," which was one of the first pieces of music to be written with the aid of a computer.

• 1957, Mathematician Donald B. Gillies, Physicist, James E. Snyder and Astronomers George C. McVittie, S. P. Wyatt, Ivan R. King and George W. Swenson of the University of Illinois used the ILLIAC I computer to calculate the orbit of the Sputnik I satellite within 2 days of its launch.

See also

• ORDVAC
• ILLIAC II
• ILLIAC III
• ILLIAC IV

External links

• ILLIAC I history including computer music.
• ILLIAC I Programmer's Manual – Including program library documentation
• I. R. King, G. C. McVittie, G. W. Swenson, Jr., and S. P. Wyatt, Jr., "Further observations of the first satellite," Nature, No. 4593, November 9, 1957, p. 943.