Happy 50th birthday 4004, and thank you!

Dr. Jon Peddie
Published 12/28/2021
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Happy birthday 4004

The chip that changed the world

Thanks to pioneering work by TI’s Jack Kilby (see TechWatch), and Fairchild’s Robert Noyce in the mid-1950s, the concept and practice of integrated circuits came to be—the incorporation of multiple transistors in logic gates. in a single device. That led to James Buie at TRW who developed the first TTL IC, and that led to commercial-off-the-shelf (COTS) logic chips—integrated circuits—ICs.

People and companies built computers using logic chips. They also built calculators.

In 1968, most ICs used bipolar technology. They were made using the groundbreaking planar process, pioneered by Fairchild in the late 1950s. It allowed Fairchild and later others to batch-fabricate silicon transistors. Competing with bipolar technology was another emergent technology, called MOS (metal oxide semiconductor) technology. Many people at the time thought it was the future of ICs.

Photo source: Thomas Nguyen, Wikipedia



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In the late 1960s, Japanese calculator company Busicom built the first calculator to employ ICs. In 1968, a young engineer at Busicom, Masatoshi Shima, worked on the design of Busicom’s first

Masatoshi Shima
Masatoshi Shima

calculator with printed output, the Busicom 141-PF.

Busicom then went to U.S. semiconductor companies, which were then the leaders in ICs at the time, to get advanced integrated circuits for its calculators and other business machines. Busicom gave two contracts, one with Mostek for an advanced LSI for Busicom’s basic calculators that were manufactured in its Osaka factory. And the second contract, in 1969, was with a start-up company, founded in 1968, called Intel. Intel was making RAM when Shima contacted them.

Busicom sent Shima to Intel on the recommendation (encouragement) of Tadashi Sasaki of Sharp, who was friends with Robert Noyce.

When Shima convinced Intel to take on the project, Intel put Marcian E. “Ted” Hoff in charge of the project with the assistance of Stanley Mazor, another Intel engineer. Mazor and

Federico Faggin, Stan Mazor, and Marcian (Ted) Hoff. (Source: Intel)
Federico Faggin, Stan Mazor, and Marcian (Ted) Hoff. (Source: Intel)

Shima would stay friends for years afterward.

Hoff was in charge of Intel’s Application Research department. In 1969, he prepared an architectural proposal consisting of a logic block with an instruction set, while talking with Busicom engineers.

Shima had one design idea, and Hoff had a different idea. Finally, Busincom management settled the debate and chose Hoff’s design.

And then one of those made in Hollywood plot twists happened. A Texas company, Datapoint, was pursuing a similar goal: reduce the number of chips to build—a small computer. Datapoint went to TI and Intel. Intel took on the project and decided they would build the chip using MOS. Intel assigned Hoff to work on the Datapoint project, which led to the 8008, but took Hoff off the Busicom project. Datapoint has been credited with designing and building the first PC, but it was for commercial use, not

Intel 4004 block diagram (Source Wikipedia, Image by Appaloosa, CC BY-SA 3.0)


Federico Faggin took over the Busicom project, but all that competition between designs plus personnel shifts in Intel delayed the project. The 4004 was consequently designed by Federico Faggin. The final design was fabricated in 10 microns, had 2250 transistors, and a 4-bit ALU with a 12-bit address in a 16-pin package. Faggin wrote about his experiences on the project, and it was published in IEEE Solid-State Circuits Magazine in 2009.

During the 1970s, microprocessors were developed, and Intel introduced the now-famous Intel 4004 in 1971, credited as being the first single-chip microprocessor. Texas Instruments also introduced a microprocessor, the TMS 1000 in the same time period. It probably will never be known which company actually had the first working microprocessor running in their lab.

The delivery of the first fully operational 4004 to Busicom took place in March 1971 and Busicom used it in its 141-PF printing calculator engineering prototype (which can be seen in the Computer History Museum in Mountain View, California). The Busicom 141 was made commercially available in July 1971.

Busicom circuit board
Busicom circuit board

Intel commercialized the 4004 and made it available on November 21, 1971. It paved the way for microprocessor computing. It was the world’s first commercially available microprocessor and can be credited with enabling the development of technology like PCs, ubiquitous computing, the cloud that we take for granted today.



The Nippon Calculating Machine Corp was incorporated in Japan in 1945 and changed its name to Business Computer Corporation, Busicom in 1967. Due to a recession in Japan in 1974, Busicom became the first major Japanese company in the calculator industry to fail.

Shima and Mazor
Shima and Mazor at the Computer History Museum’s 2009 Fellows Award event, where they were inducted, Fellows. (Source: Wikipedia)

Nigel Tout has written a fabulous background story on the triangular relationship between Robert Noyce and Tadashi Sasaki of Sharp, and Sasaki’s behind-the-scenes help for Busicom.

50 years on November 15, 1971, Intel introduced the 4004 and with it the modern-day computer age. The 4004 was the industry’s first commercially-available microprocessor and its instruction set is still at the heart of contemporary CPUs. It takes its place among other venerable engines that changed the world like the steam engine and the internal combustion engine.



Faggin, F. (2009) The Making of the First Microprocessor, IEEE Solid-State Circuits Magazine ( Volume: 1, Issue: 1, Winter 2009), https://ieeexplore.ieee.org/abstract/document/4776530