24-BIT

The IBM System/360, announced in 1964, was an extremely popular computer system with 24-bit addressing and 32-bit general registers and arithmetic. The early 1980's saw the first popular personal computers, including the IBM PC/AT with an Intel 80286 processor using 24-bit addressing and 16-bit general registers and arithmetic, and the Apple Macintosh 128k with a Motorola 68000 processor featuring 24-bit addressing and 32-bit registers.