Happy 50th birthday to the Intel 4004

The chip that changed the world

Jon Peddie
 (Source: Thomas Nguyen for Wikipedia)


The pioneering work by TI’s Jack Kilby (see TechWatch), and Fairchild’s Robert Noyce in the mid-1950s, led to the integrated circuit, multiple transistors combined in the logic gate of a single device. That led to James Buie at TRW who developed the first TTL IC (transistor-transistor logic integrated circuit), and that led to commodity off-the-shelf (COTS) logic chips.

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

Masatoshi Shima

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 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 design 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 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 assigned Hoff to work on the Datapoint project, which led to the 8008, but took Hoff off the Busicom project. Busicom gave two contracts, one with Mostek for an advanced LSI design for Busicom's basic calculators that were manufactured in its Osaka factory. Datapoint has been credited with designing and building the first PC, but it was for commercial use, not consumers. (The birth of the personal computer: everything you know is wrong Unless you lived in Texas in the 70s). 

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


Federico Faggin took over the Busicom project, but the competition between designs and personnel shifts in Intel delayed the project. The 4004 was consequently designed by Federico Faggin. The final design was fabricated in 10 micron, had 2250 transistors, and a 4-bit ALU with a 12-bit address in a 16-pin package.

During the 1970s, microprocessors were developed, and Intel introduced the now-famous Intel 4004 in 1971. It is considered 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.


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.

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.

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