Rick Robinson

Nov 13th 2020

Seymour Cray and the Birth of the Supercomputer


In the beginning, there were electronic brains. That was the name that newspapers gave to the first digital computers in the postwar 1940s, described by the Association for Computing Machinery (ACM) as “vast, unreliable beasts built with vacuum tubes and mercury memory.”

One of the standout engineers who wrestled with these vast, unreliable beasts was Seymour Cray, a young World War II veteran and Wisconsin native. As a boy during the 1930s, he used Erector Set components to build a device that read in paper-punched tape and converted the hole pattern to Morse code signals, according to the Star Tribune. This innovative spirit would help Cray become known as the father of supercomputing.

A Technology Frontier

In 1950, while still in college, Seymour Cray went to work for a company called Engineering Research Associates (ERA) that built code-breaking technology and also dipped its toes into the newly emerging technology of digital computers.

Cray first made his mark, according to ACM, with the ERA 1103, also known as the UNIVAC 1103. It was the first commercially successful scientific computer.

In the late 1950s, Cray joined several colleagues from ERA in starting a new company, Control Data Corporation (CDC). But Cray was growing tired of designing ordinary 1950s commercial computers. His goal aimed higher than that, reports the ACM: He wanted to design the largest computer in the world.

“The Largest Computer in the World”

The very expression takes us into a very different era of computing. Computers could take up an entire room — or even an entire floor of a building. Desktop computers didn’t exist yet, let alone handheld computing devices like smartphones. What Seymour Cray really wanted was to design the fastest computer in the world.

And that was exactly what he went on to do. His key insight was that while the central processing unit (CPU) does the actual computing in a computer, building a fast computer took more than just a fast processor. Without faster input and output, a fast processor would be left to twiddle its electronic thumbs while it waited for information to get in and out. Said Cray, per ACM, “Anyone can build a fast CPU. The trick is to build a fast system.”

Performing that trick meant a lot of attention to detail. He adjusted the lengths of wires so that input signals that were needed at the same time would all actually arrive at the same time, and the system wouldn’t have to wait for one signal that came through a longer wire.

Maximum speed also meant additional focus on the cooling system. Cray built an interlock so that a cooling failure would automatically shut down the computer before it could overheat. When a customer called about a problem with a computer encased in ice, Cray realized that the interlock needed to go both ways. The customer’s computer had shut down due to a transient power loss, but the cooling system had kept on going, hence the solid block of ice, according to IEE Computer Society.

His work culminated in 1976 with the Cray-1. In its day it was the fastest multipurpose computer in the world, rivaled only by a single one-off machine that could match its speed for highly specialized tasks, reports IEE Computer Society. Supercomputers entered the vocabulary of the technology world. And the name Seymour Cray was all but synonymous with supercomputing.

Speed Goes On

Supercomputer technology was well-established by the time Cray died in 1996. By that time desktop computing was also widespread, and home computers could match the performance of Cray’s pioneering efforts.

The internet was also taking off. By the turn of the new century, the popular conversation centered more on computer networks than on even the most powerful individual computers. Today, companies that might once have invested in a Cray machine are more likely to invest in cloud computing, relying on external networks without even knowing what actual machines are doing the work.

But supercomputer technology continues to progress. Current generation machines have achieved speeds in the petaFLOPS — around 10 million times faster than the original Cray-1. Both the Department of Energy and NOAA are working on a new generation that will be at least 10 times faster.

Even Seymour Cray would likely be impressed.