CDC 6600

CDC 6600

The CDC 6600 was built by a man who left town to build it. Seymour Cray, frustrated with corporate interference at Control Data's Minneapolis headquarters, decamped to a lab in Chippewa Falls, Wisconsin, and — with a team of just 34 people — produced in 1964 a machine roughly ten times faster than the IBM 7090 that defined the previous era's peak. It was the first computer the industry called a supercomputer, and for five years there was no argument about which machine was the world's fastest.^[1]

The engineering was architectural minimalism taken to its extreme: a 60-bit central processor at 10 MHz with a RISC-like, small instruction set, cooled by circulating Freon refrigerant so the circuits could be packed tighter than air allowed. The key structural move was the ten peripheral processors — small dedicated machines that handled all I/O, leaving the central processor to do nothing but compute. The division of labor meant the 6600's CPU never waited on a card reader — the architecture that later every supercomputer and, eventually, every DMA engine and coprocessor would re-invent.^[2]

What it obsoleted

The 6600 made the previous generation's flagships look silly — IBM's own STRETCH project had just shipped the 7030, far slower and at far greater cost and team size. Cray's response to bureaucracy was thirty-four people and a drawing board; the result outperformed IBM's flagship programs by an order of magnitude and sold over a hundred units at $2.37 million each. The machine ran SCOPE and KRONOS — operating systems almost as legendarily difficult as the hardware was brilliant.^[3]

Where it sits

The 6600 is the machine the supercomputer era starts with — and its design method (small team, remote lab, no compromise) became the Cray legend that produced the 7600, the Cray-1, and the entire vector-supercomputing genre. It also closed the loop Whirlwind opened: a machine so fast it made speed itself a product category.

Check your understanding

• Who designed the 6600 — and where did he build it to escape corporate interference?
• What did the ten peripheral processors do?
• How much faster was it than the era's previous flagship?
• What cooling technology kept it dense enough to be fast?