ILLIAC IV shuts down, September 7, 1981

-September 07, 2017

The ILLIAC IV, one of the first supercomputers ever built, was shut down on September 7, 1981 after almost a decade of service. ILLIAC (Illinois Automatic Computer) was a series of supercomputers, some built at the University of Illinois at Urbana-Champaign.

The machine’s design featured fairly high parallelism with up to 256 processors, used to allow it to work on large data sets in what would later be known as vector processing.



The University of Illinois signed a contract with DARPA in 1964 to start work on the computer. Development started the next year, and a first-pass design was completed in 1966. When the machine’s purpose came under scrutiny from students protesting the Vietnam War, it was moved from the school to Burroughs Corporation's facility in Paol, Pa. There, it took six years to build the computer, which cost $40 million. It was the fastest machine in use at the time.

ILLIAC featured ECL (emitter coupled logic) ICs from Texas Instruments, specialized disk drives that could store about 80 MB per 36" disk, and each processing element had 2048-words of 240 ns thin film memory. The plan was for it to have the ability to process 1 billion floating point operations per second, but as the project fell behind schedule, the result was much slower.

To test the computer, several new computer languages were created, including IVTRAN and TRANQUIL, parallelized versions of FORTRAN, and Glypnir.

The computer was delivered to NASA's Ames Research Center outside of San Francisco in 1971. ILLIAC IV was connected to the ARPANET for distributed use in November 1975, becoming the first available supercomputer, beating the Cray-1 by nearly a year.

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Editor's note: This article was originally posted on September 7, 2012 and edited on September 7, 2017.

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