KRISHNA PALEM’S computers won’t win any awards for accuracy. Most of the time they can’t even add up correctly. For them, 2 + 2 might as well be 5. But don’t be fooled by the wobbly arithmetic. Palem is making machines that could represent a new dawn for computing.
Inaccuracy is not something we typically associate with computers. Since Alan Turing laid down their ground rules in the 1930s, computers have been sticklers for precision, built on the principle of following step-by-step instructions in an exact and reproducible manner. They should not make errors.
But maybe we should cut them some slack. Letting computers make mistakes could be the best way to unlock the next wave of smart devices and prevent high-performance computing hitting a wall. It would allow us to run complex simulations that are beyond today’s supercomputers – models that better predict climate change, help us design more efficient cars and aircraft, and reveal the secrets of galaxy formation. They may even unlock the biggest mystery of all, by letting us simulate the human brain.
Until now, we have had to accept a trade-off between performance and energy efficiency: a computer can be either fast or low-powered, but not both. This not only means that, but also that supercomputers are energy guzzlers. Next-generation “exaflop” machines, which are capable of 1018 operations a second, could consume as much as 100 megawatts, the output of a small power station. So the race is on to make computers do more with less.
One way is …