The
Hewlett-Packard FOCUS microprocessor, launched in 1982, was the first commercial, single chip, fully
32-bit microprocessor available on the market. At this time, all
32-bit competitors (
DEC,
IBM,
Prime Computer, etc.) used multi-chip
bit-slice-CPU designs. The FOCUS architecture (Focus CPU, Focus I/O processor (IOP), Focus memory controller (MMU), 16
KB x8 dynamic
RAM, and a timer) was used in the Hewlett-Packard HP 9000 Series 500 workstations and servers (originally launched as the HP 9020 and also, unofficially, called HP 9000 Series 600). It was a
stack architecture, with over 220 instructions (some 32 bits wide, some 16 bits wide), a segmented memory model, and no general purpose programmer-visible
registers. The design of the FOCUS CPU was richly inspired by the custom
silicon on sapphire (SOS) chip design, HP used in their
16-bit HP 3000 series machines.