Physics books should get a makeover as HP announced a remarkable discovery: the fourth fundamental unit of electronic circuits: the ‘memristor’. The new ‘memory resistor’ will join the capacitors, inductors and resistors class, but at the same time, it will exceed their capabilities, by its unique ability to remember what previously happened to it.

This discovery, unveiled by the HP Labs in Palo Alto, California in the journal Nature, will revolutionize computer world, making it a whole lot easier to revert to a previous state without having to boot up the computer. This means the computer will be able to turn off and on almost instantly, returning to its previous state.

“A memristor is essentially a resistor with memory,” said Stan Williams of the HP Labs. “The actual resistance of the memristor changes depending on the amount of voltage and the time for which that voltage has been applied to the device.”

The idea of the memristor is not a new one, as it first started circulating 37 years ago, when Leon Chua, an electrical engineer at the University of California, Berkley suggested it in a 1971 paper. Unfortunately, it took decades for scientists to actually transpose the idea into reality.

“The original prediction and the papers in which the prediction appeared were very heavy mathematically, so it required a very significant investment in order to read those papers,” Stan Williams explained.

Now that memristors are real, Leon Chua believes they will play an essential role in the development of ‘non-volatile’ memory, which shouldn’t decay when the power is switched off. This type of memory is currently used for flash devices rather than regular computers, because volatile memory offers faster access to data, but things are expected to change.

The announcement comes after IBM researchers have described in two papers published in the April 11 issue of Science a technology that could change radically the way we are storing our electronic data by using racetrack memory, which combines the main advantages of flash memory and hard drives, offering not only the high performance and reliability of flash, but also high capacity and low costs.