Influenced by the relative speed, efficiency and design of the 6502, as well as publications from the University of California on RISC chip designs, the ARM - or Acorn RISC Machine - started out as Acorn's answer to the burgeoning IBM PC market, as well as the new 32-bit processors like Motorola's 68000 which had started appearing in the early 1980s.

Surveying the scene and deciding that existing 16-bit processor didn't really given them much more performance than the already-fast BBC Micro, and that current 32-bit chips were too expensive to build around, Acorn instead decided to design its own from scratch. The first simulation of the ARM architecture appropriately ran on a BBC Micro with a second 6502 CPU.

The ARM2 appeared in late 1986, where it was found to be about seven times as fast as Motorola's 68000, and even twice as fast as Intel's 80386, despite having a slower clock speed.

It's thought that over 230 billion ARM-based chips have been produced since the early 2000's.