In May, researchers at Hewlett-Packard (HP) unveiled their long-anticipated “memristor,” [subscription required] a device only a few nanometers wide that could revolutionize computer memory and help researchers build a machine that functions like a human brain.
For decades, the memristor—short for memory resistor—had been little more than an engineer’s dream: a circuit element with high-density memory and low energy requirements. The dream dated back to 1971, when electrical engineer Leon Chua described a theoretical fourth circuit element that would function along with the traditional trio of resistor, inductor, and capacitor. Unlike those other circuit components (and modern transistors), the memristor could retain information even after the current shuts off. In theory, a memristor-driven computer could boot instantly and have a much smaller power demand than current machines.
Modern computers use magnetic hard drives for long-term memory and RAM (random access memory) for short-term memory. R. Stanley Williams, a senior fellow at HP who led the research, says the memristor’s abilities place it somewhere between the two. “Memristors could expand in both directions and take over much of what is already being done,” he says.
According to Williams, memristors function in many ways like neural synapses, which can retain information and grow stronger with use. In the future, he says, memristors could serve as artificial synapses in computers that function like human brains. A memristor-based machine could perform some tasks, like voice or face recognition, much better than any machine today, Williams says, adding, “At least in theory, a machine [based on memristors] could do those things almost instantaneously with no waste of time or energy.”
