By Robert McMillan | Wired
By definition, a computer is a machine that processes and stores data as ones and zeroes. But the U.S. Department of Defense wants to tear up that definition and start from scratch.
Through its Defense Advanced Research Projects Agency (Darpa), the DoD is funding a new program called UPSIDE, short for Unconventional Processing of Signals for Intelligent Data Exploitation. Basically, the program will investigate a brand-new way of doing computing without the digital processors that have come to define computing as we know it.
The aim is to build computer chips that are a whole lot more power-efficient than today’s processors — even if they make mistakes every now and then.
The way Darpa sees it, today’s computers — especially those used by mobile spy cameras in drones and helicopters that have to do a lot of image processing — are starting to hit a dead end. The problem isn’t processing. It’s power, says Daniel Hammerstrom, the Darpa program manager behind UPSIDE. And it’s been brewing for more than a decade.
“One of the things that’s happened in the last 10 to 15 years is that power-scaling has stopped,” he says. Moore’s law — the maxim that processing power will double every 18 months or so — continues, but battery lives just haven’t kept up. “The efficiency of computation is not increasing very rapidly,” he says.
Hammerstom, who helped build chips for Intel back in the 1980s, wants the UPSIDE chips to do computing in a whole different way. He’s looking for an alternative to straight-up boolean logic, where the voltage in a chip’s transistor represents a zero or a one. Hammerstrom wants chipmakers to build analog processors that can do probabilistic math without forcing transistors into an absolute one-or-zero state, a technique that burns energy.
It seems like a new idea — probabilistic computing chips are still years away from commercial use — but it’s not entirely. Analog computers were used in the 1950s, but they were overshadowed by the transistor and the amazing computing capabilities that digital processors pumped out over the past half-century, according to Ben Vigoda, the general manager of the Analog Devices Lyric Labs group.
“The people who are just retiring from university right now can remember programming analog computers in college,” says Vigoda. “It’s been a long time since we really questioned the paradigm that we’re using.”