ILLIAC II
The ILLIAC II was the first transistorized and pipelined supercomputer built by the University of Illinois. It was an asynchronous logic design. At its inception in 1958 it was 100 times faster than competing machines of that day. It became operational in 1962, two years later than expected.
ILLIAC II had 8192 words of core memory, backed up by 65,536 words of storage on magnetic drums. The core memory access time was 1.8 to 2 µs. The magnetic drum access time was 7 µs. A "fast buffer" was also provided for storage of short loops and intermediate results (similar in concept to what is now called cache). The "fast buffer" access time was 0.25 µs
The word size was 52 bits. Floating-point numbers used a format with 7 bits of exponent (power of 4) and 45 bits of mantissa. Instructions were either 26 bits or 13 bits long, allowing packing of up to 4 instructions per memory word. The pipelined functional units were called advanced control, delayed control, and interplay. The computer used Muller speed-independent circuitry (i.e. Muller C-Element) for a portion of the control circuitry.
In 1963 Donald B. Gillies (who designed the control) used the ILLIAC II to find three Mersenne primes, with 2917, 2993, and 3376 digits - the largest primes known at the time.
Hideo Aiso (相磯秀夫?, 1932-) from Japan participated in the development program and designed the arithmetic logic unit from September 1960.
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