A new blueprint for microprocessors challenges the industry’s giants

MOST MICROPROCESSORS—the chips that do the grunt work in computers—are built around designs, known as instruction-set architectures (ISAs), which are owned either by Intel, an American giant, or by Arm, a Japanese one. Intel’s ISAs power desktop computers, servers and laptops. Arm’s power phones, watches and other mobile devices. Together, these two firms dominate the market. Almost every one of the 5.1bn mobile phones on the planet, for example, relies on an Arm-designed ISA. The past year, however, has seen a boomlet in chips made using an ISA called RISC-V. If boomlet becomes boom, it may change the chip industry dramatically, to the detriment of Arm and Intel, because unlike the ISAs from those two firms, which are proprietary, RISC-V is available to anyone, anywhere, and is free.

An ISA is a standardised description of how a chip works at the most basic level, and instructions for writing software to run on it. To draw an analogy, a house might have two floors or three, five bedrooms or six, one bathroom or two. That is up to the architect. An ISA, however, is the equivalent of insisting that the same sorts of electrical sockets and water inlets and outlets be put in the same places in every appropriate room, so that an electrician or a plumber can find them instantly and carry the correct kit to connect to them.