Four-Phase Systems

Four-Phase Systems, Inc.

File:Four-Phase Systems logo.svg
Industry	Semiconductor
Founded	1969
Founder	Lee Boysel
Defunct	1982
Fate	Acquired by Motorola
Headquarters	Cupertino, CA, USA
Products	Semiconductor main memory, LSI MOS logic, central processing unit, microprocessor
Owner	Motorola

Four-Phase Systems, Inc. was a pioneering semiconductor computer enterprise established by Lee Boysel in 1969. The company specialized in early computing systems that utilized semiconductor main memory alongside MOS LSI logic technology. It attained moderate market success before being purchased by Motorola in 1982.

History

The idea emerged when Boysel, working at Fairchild Semiconductor, designed MOS devices in 1967 and proposed constructing a computer from a minimal set of MOS chips. As head of Fairchild’s MOS design division, he developed components aligned with this concept prior to founding Four-Phase in late 1968 with a team of engineers from Fairchild. Notably, Robert Noyce, co-founder of Intel, was an early board member of Four-Phase.

Boysel arranged for chip manufacturing through Cartesian, a wafer fabrication company started by another Fairchild engineer. By spring 1970, Four-Phase had produced an engineering prototype and presented it at the Fall Joint Computer Conference. By 1971, the IV/70 system was operational with four customers; by 1973, the company had shipped 347 systems to 131 clients.

In 1979, Four-Phase reported revenues totaling $178 million. Its product range included multiple System IV models designed to address diverse data processing requirements:

Model	Announced	First Delivery
IV/30	Dec 1976	Dec 1976
IV/40	Mar 1973	Jul 1973
IV/50	Jun 1976	Q4 1976
IV/55	Dec 1976	Dec 1976
IV/60	—	—
IV/65	Apr 1979	Jun 1979
IV/70	Sep 1970	Feb 1972
IV/90	Jun 1977	Jul 1977

Entry-level models such as the IV/30 and IV/55 supported one or two data entry terminals; mid-tier models starting with the IV/40 accommodated multiple high-capacity stations; while higher-end units like the IV/60 series could be configured as compact computer systems.

To broaden its semiconductor product offerings and enhance market presence, Motorola acquired Four-Phase in a stock transaction valued at $253 million in 1982 (equivalent to approximately $today). The former headquarters located in Cupertino now forms part of Apple’s Infinite Loop campus.

System

The central processing unit developed by Four-Phase featured a 24-bit word length and was implemented on a single circuit card containing three AL1 processors, three ROM chips, and three random logic chips. Memory modules incorporated Four-Phase’s proprietary 1K RAM chips. The architecture integrated a video controller capable of supporting up to 32 terminals through a character buffering mechanism.

AL1 chip

The AL1 is an eight-bit bit-slice microchip that includes eight registers and an arithmetic logic unit (ALU). It employs four-phase logic design encompassing over one thousand gates within a compact die measuring approximately 3.3 mm by 3 mm. Although it was not initially marketed as a microprocessor, the AL1 gained recognition as one during litigation in the 1990s concerning Texas Instruments’ microprocessor patent claims. During courtroom demonstrations, Boysel showcased the AL1 functioning alongside ROM, RAM, and I/O peripherals as a microcode controller orchestrating memory access and ALU operations.

The AL1 chipset is regarded as one of the earliest commercially utilized microprocessors, predating or contemporaneous with the Intel 4004 in business applications. This development underscores Four-Phase Systems’ pioneering role in advancing microprocessor technology and its strategic influence on the evolution of computing hardware within the industry.

References

• Lee Boysel – Insights on Achieving Your First Million and Advice for Emerging Entrepreneurs

External links

• Four-Phase Systems AL1 Processor – 8-bit Design by Lee Boysel