 In October 1983, Wilson began designing the instruction set for one of the first reduced instruction set computer (RISC) processors, the Acorn RISC Machine (ARM), The ARM1 was delivered on 26 April 1985 and worked first time.This processor type was later to become one of the most successful IP cores – a licensed CPU core – and by 2012 was being used in 95% of smartphones.Wilson designed Acorn Replay, the video architecture for Acorn machines.