HP FOCUS

At this time, all 32-bit competitors (DEC, IBM, Prime Computer, etc.)

[2] It was a 32-bit implementation of the 16-bit HP 3000 computer's stack architecture,[3] with over 220 instructions (some 32 bits wide, some 16 bits wide), a segmented memory model, and no general purpose programmer-visible registers.

[4] The design of the FOCUS CPU was richly inspired by the custom silicon on sapphire (SOS) chip design HP used in their HP 3000 series machines.

Because of the high density of HP's NMOS-III IC process,[5] heat dissipation was a problem.

Therefore, the chips were mounted on special printed circuit boards, with a ~1 mm copper sheet at its core, called "finstrates".

Hewlett-Packard HP9000 Series 500 FOCUS-CPU; NMOS-III Finstrate CPU - 32Bit - 18 MHz - consist of five chips on one board: CPU, IO-Processor (IOP), Memory Controller (MMU), 16kx8 DRAM, Clock Chip - 450000 FETs - HP Part Number: 5061-6803 - front side look modified with transparent chip covers
HP FOCUS processor and support chips on "finstrate" board