Seymour Cray: Obituary

Throughout his working life Seymour Cray pursued a single-minded vision to build the fastest computers of which the technology of the day was capable. His legacy is in the firm Cray Research, the leading supplier of supercomputers, whose top-of-the-range machines are currently capable of performing over 50 billion calculations a second.

Born in 1925, in Chippewa Falls, Wisconsin, Cray was the son of an engineer. After serving as an electrician in the US army, he took bachelors and masters degrees in Electrical Engineering and Mathematics at the University of Minnesota, Minneapolis. In 1951, aged 26, he joined the Minneapolis- based ERA computer company, one of the first post-war computer start-ups, and founded by the entrepreneur William Norris.

At ERA, Cray led the design of mainframe computers, the best known of which was the model 1103. Following the acquisition of ERA by the business- machine conglomerate Remington Rand, this was successfully marketed as the Univac 1103.

Somewhat stifled by big-firm bureaucracy, Norris and a group of executives and engineers who included Seymour Cray decided to strike out on their own as the Control Data Corporation in 1957. Cray was given the brief to design high-performance computers, which were sold principally to government research organisations and defence contractors.

Later known as "supercomputers", these machines were used in military applications such as design calculations for atomic weapons and code-breaking, as well as relatively peaceful uses such weather forecasting, the modelling of complex systems, and in the aerospace industry.

As CDC expanded though its own success, Cray found it increasingly difficult to work within a large organisation, and decided to leave to form his own company. Instead, Norris offered to build Cray a laboratory in his home town of Chippewa Falls, so that he could continue designing computers without distraction. Over the next few years Cray earned a reputation as something of a recluse, rarely venturing from Chippewa Falls, and reputedly allowing Norris just two visits a year.

In the Chippewa Falls laboratory Cray designed his next computer, the path-breaking CDC 6600 announced in 1963. Selling for the (then) modest price of $7.5m, the machine could perform 3 million calculations per second.

The delivery of the CDC 6600 coincided with the announcement of IBM's System/360 general-purpose computer range. The IBM announcement devastated many of IBM's competitors, but by focusing on the niche market of very fast computers in which IBM was relatively weak, Control Data prospered throughout the 1960s.

In the early 1970s, recognising the limited size of the market for high-performance computers, Norris decided to diversify into other computer activities, and supercomputers were downgraded in importance.

In 1972, Cray therefore decided to leave Control Data to form Cray Research in Chippewa Falls, which would be dedicated exclusively to building supercomputers. It was a friendly parting, with Control Data putting up $500,000 start- up money and deciding to exit from the supercomputer business altogether.

The first computer produced by Cray's new firm, the CRAY-1, was delivered to Los Alamos National Laboratory in spring 1976 and was immediately recognised as a design classic. Not the least striking aspect of the machine was its visual appearance: jokily referred to a "the world's most expensive loveseat", the low-slung machine was built around a cylindrical structure contaning the main processing units. This geometrical arrangement minimised the lengths of the internal connecting wires (because electric signals take one billionth of a second to travel one foot, this was a significant design issue).

The $5m machine could perform over 100 million calculations a second - about a hundred times as fast as big mainframe computers of the period. Over 60 machines were eventually sold. A successor machine, the CRAY-2, also sold well, establishing Cray Research as the dominant supercomputer manufacturer, with a three-quarters market share.

Seymour Cray had a distinctive creative style, preferring to design each new machine from the ground up, starting with a "blank piece of paper". However, as Cray Research expanded, the emphasis inevitably had to change from raw innovation to a more gradual evolution of its existing products. This left Cray dissatisfied, and he decided to break away once more to form a new company. Incorporated as Cray Computer in 1992, the new company was based in Colorado Springs.

Its first machine, the CRAY-3, was announced in 1993, and promised a speed of 16 billion calculations a second. A successor machine, the CRAY- 4, never materialised, because of the downturn in the supercomputer industry following US cuts in defence procurement.

With the end of the Cold War, government spending on supercomputers was cut heavily. While private industry had begun to use supercomputers for activities such as futures forecasting and data-mining, this was not sufficient to sustain the industry. Several supercomputer firms folded, including Cray Computer in 1995.

Notwithstanding the lean times in the industry, the 70-year-old Seymour Cray quickly launched another venture and continued to do what he did best - design high-performance computers. His programme was cut short when he was severely injured in a motor accident on 22 September, from which he never recovered.

Seymour Cray, computer builder: born Chippewa Falls, Wisconsin 28 September 1925; married Geri Harrand (one son, two daughters); died Colorado Springs 6 October 1996.