suring 1 kilometer on a side—a job for an exaflop machine, one with 1000 times more computing power than even Roadrunner can provide.

Wehner, Oliker, and Shalf estimate that a general-purpose machine using today’s technology would cost $1 billion to build and 200 megawatts to power—enough for a small city. By comparison, they estimate, a specialized machine would cost just $75 million and consume just 4 MW.

The researchers are now trying to validate their claims with a hardware mock-up, which they are building in collaboration with Tensilica, a custom-chip supplier in Santa Clara, Calif. The plan

is to bench-test a single processor by November and a parallel array of processors by the middle of 2009. If the claims are vindicated, the researchers hope to get government funding for a full-size machine.

Critics of special-purpose machines say they’ve heard it all before. “The problem is that when we devise a new way to solve a problem, the machine designed for the old way will no longer be as good,” says Jack Dongarra, a professor of electrical engineering and computer science at the University of Tennessee.

But according to Horst Simon, who heads the Lawrence Berkeley lab’s

research computing center, the proposed machine would not be so specialized that a new algorithm would render it instantly obsolete.

“We are building hard-ware that runs not just one algorithm but a large class of related algorithms,” he says.

“We are trying to eliminate unessential features of the architecture, much of it devel-oped for desktop applica-tions, and to optimize it for a class of applications that is scientifically focused.”

Not that there wouldn’t still be room for superspecialized machines. As IEEE Spectrum went to press, D.E. Shaw Research of New York City said that by the end of the year it will have a specialized machine, called Anton, that can simulate molecular inter-actions hundreds of times as fast as anything now available.

—Philip E. Ross

A Better Camera Pill A collaboration of engineers led by the Fraunhofer Institute for Biomedical Engineering, in St. Ingbert, Germany, has developed the first-ever control system for a camera pill. Natural motions propel today’s camera pills through the esophagus too fast to take all the pictures that doctors would like to see. The Fraunhofer pill is steered using an external magnet held by a physician. “In the future, doctors will be able to stop the camera in the esophagus, move it up and down, and turn it,” says Frank Volke, a researcher at Fraunhofer.photo: FraunhoFer InstItute For bIomeDIcal enGIneerInG

efficiency of World’s top 10 Supercomputers:Average power consumption » 1.32 megawatts

Average power efficiency » 248 floating-point operations per second per watt

yearly electricity cost* » us $ 1 029 124

*Assumes constant operation at $0.089 per kilowatt-hour.

Source: Consumption and efficiency from Top500.org.

12 NA • IEEE spEctrum • August 2008 www.specTrum.ieee.org