ILLIAC IV - ILLIAC Moves

ILLIAC Moves

When the computer was being built at the Burroughs Corporation's Great Valley Lab in the late 1960s, it was met with hostility by protesters who were suspicious of the University's tie with the Department of Defense (through ARPA), and felt that the University had sold out to a conspiracy to develop nuclear weapons. The fear was unfounded, but government paranoia was running rampant in the time following the massacre at Kent State University. The protests reached a boiling point on 9 May 1970, in a day of "Illiaction". the Director of the Project decided the University could not guarantee the safety of the machine. It was then decided that the machine would be delivered to the NASA Ames Research Center, rather than to Illinois. The work was picked up by NASA, then still cash-flush in the post-Apollo years and interested in almost anything "high tech". They formed a new Advanced Computing division, and the machine was delivered to NASA Ames.

The failure of TI to deliver the LSI chips required significant re-design and delayed completion of the machine until 1971. By this time the original $8 million estimated from the first design in 1966 had risen to $31 million. Burroughs, unfamiliar with parallel test processes, could never get the computer to reach its estimated 1 GFLOPS; the best they could muster was 250 MFLOPS, with peaks of 150. NASA also decided to replace the B6500 with a PDP-10, which were in common use at Ames, but this required the development of new compilers and support software. When the ILLIAC was finally turned on in 1971, NASA's changes proved incompatible with the original design, causing intermittent failure. Efforts to correct the reliability allowed it to run its first complete program in 1972, and go into full operation in 1975. Due to MASA regulations that the computer, prone to overheating, could not be operational without observation, the machine was operated only Monday to Friday and had up to 40 hours of planned maintenance a week.

Nevertheless the ILLIAC was increasingly used over the next few years, and Ames added their own FORTRAN version, CFD. On problems that could be parallelized the machine was still the fastest in the world, outperforming the CDC 7600 by two to six times, and it is generally credited as the fastest machine in the world until 1981. For NASA the machine was "perfect", as its performance was tuned for programs running the same operation on lots of data, which is exactly what computational fluid dynamics is all about. The machine was eventually decommissioned in 1982, and NASA's advanced computing division ended with it.

Burroughs was able to use the basic design for only one commercial system, the Parallel Element Processing Ensemble, or PEPE. PEPE was designed to allow high-accuracy tracking of 288 incoming ICBM warheads, each one assigned to a modified PE. Burroughs built only one PEPE system, although a follow-on design was built by Bell Labs.

The ILLIAC IV control unit and one processing element chassis is now at the Computer History Museum in Mountain View, California.