Today, silicon microchips underlie every aspect of digital computing. But their dominance was never a foregone conclusion. Throughout the 1950s, electrical engineers and other researchers explored many alternatives to making digital computers.
One of them seized the imagination of the U.S. National Security Agency (NSA): a superconducting supercomputer. Such a machine would take advantage of superconducting materials that, when chilled to nearly the temperature of deep space—just a few degrees above absolute zero—exhibit no electrical resistance whatsoever. This extraordinary property held the promise of computers that could crunch numbers and crack codes faster than transistor-based systems while consuming far less power.
For six decades, from the mid-1950s to the present, the NSA has repeatedly pursued this dream, in partnership with industrial and academic researchers. Time and again, the agency sponsored significant projects to build a superconducting computer. Each time, the effort was abandoned in the face of the unrelenting pace of Moore's Law and the astonishing increase in performance and decrease in cost of silicon microchips.
Now Moore's Law is stuttering, and the world's supercomputer builders are confronting an energy crisis. Nuclear weapon simulators, cryptographers, and others want exascale supercomputers, capable of 1,000 petaflops—1 million trillion floating-point operations per second—or greater. The world's fastest known supercomputer today, China's 34-petaflop Tianhe-2, consumes some 18 megawatts of power. That's roughly the amount of electricity drawn instantaneously by 14,000 average U.S. households. Projections vary depending on the type of computer architecture used, but an exascale machine built with today's best silicon microchips could require hundreds of megawatts.
From IEEE Spectrum
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