Intel marks 40 years of the 4004 microprocessor

A 1971 breakthrough that changed the world

CHIPMAKER Intel today celebrates the 40th anniversary of the 4004, the world's first commercially available microprocessor.

To call Intel's 4004 just a microprocessor is to do the microelectronics world a great disservice. Not only was the Intel 4004 the first commercial microprocessor, shattering what people thought of computers, it signaled Intel's shift away from manufacturing memory and into what was going to become the industry that changed the world forever.

Back in 1969 when Japanese calculator outfit Nippon Calculating Machine Corporation asked Intel to design 12 chips for a business calculator called Busicom, Intel had already achieved some success with its memory business. Although Intel was far from being a market leader, the two 'Fairchildren', Robert Noyce and Gordon Moore were busy making money fabbing RAM chips, but not for much longer.

Back in 1969, Intel didn't have the luxury of saying no to business and Federico Faggin, Ted Hoff and Masatoshi Shima got to work on designing a processor for the relatively mundane business calculator. Later Hoff remarked that in the late 1960s it simply wasn't feasible to talk about personal computers.

Like the birth of many revolutionary pieces of engineering, the 4004 was designed by a bunch of engineers working into the night on the promise of creating something completely different.

While Faggin, who had also worked at Fairchild Semiconductor with Noyce and Moore, was busy designing the 4004 Hoff is widely credited with coming up with the architecture. Faggin built Hoff's architecture, with the legend saying that the first wafers came back to Intel's Santa Clara offices at 6PM just as everyone was clocking out for the day. Faggin pulled an all nighter in the lab to check whether the first baked 4004 actually worked, and at 3AM, overcome with exhaustion and satisfied that the radical 4004 did the job, he went home to tell his wife, "It works!".

Faggin was so proud of his design that he etched his initials, FF, on one side of the 4004's design. In later iterations of the 4004 the initials were moved, but just like an artist, Faggin signed his own work. And make no mistake, the 4004 processor is a work of art.

It might sound bashful, but Intel's 4004 wasn't particularly powerful, and the firm admitted, "The 4004 was not very powerful, it was primarily used to perform simple mathematical operations in a calculator called Busicom." However Noyce and Moore realised that it wasn't the 4004 itself that was important but its architecture.

In terms of complexity, Intel's 4004 had 2,300 MOS transistors and was fabricated on a 10,000nm process node on 60mm wafers. In a graphic illustration of Moore's law, processors from Intel and AMD today typically have hundreds of millions of transistors and are fabricated on the 32nm process node on 300mm wafers. But the numbers simply don't tell the whole story, the fact is that the 4004 was not just a new chip with a new micro-architecture, but it was a radical new way of thinking and building processors.

What Faggin, Hoff and Shima had created with the 4004 was the ability to commoditise computing by adding the micro in microprocessors. Prior to the 4004, general purpose computers were the hulking machines you saw in black-and-white films as room-sized equipment. Henry Ford brought the motorcar to the wider public through mass production, while Intel brought computing to the masses by miniaturising it.

Intel showed what would become perhaps the first known example of its shrewd business policies by offering Busicom, now a company in its own right, a reported $60,000 for the design and marketing rights for the 4004. Busicom agreed to the deal and, even though a year later the firm went bust, Intel was left with the ability to sell the 4004, which it did in 1971.

In what would become standard Intel behaviour, the firm courted developers for its 4004 processor. Even at that time, Intel knew that software held the key to its success, and it wasn't wrong.

Like Noyce and Moore, Faggin chose to form his own company in 1974 called Zilog. The firm is extremely successful in embedded CISC processors but is best known for producing chips that were found in the Sinclair ZX Spectrum. Faggin still heads up Zilog but his name will forever be associated with the creation of arguably the 20th century's most important innovation in electronics. Shima followed Faggin to Zilog in 1975 and worked on the Z80 and Z8000.

Hoff stayed on at Intel, becoming an Intel Fellow and more recently was awarded the National Medal of Technology and Innovation in 2009 by US President Barack Obama, a year before Faggin received the same award.

What Faggin, Hoff and Shima created wasn't just a microprocessor, it was a blueprint for others to follow and quite simply extended what was thought possible. Credit should be given to Noyce, Moore and Intel's third co-founder, Andy Grove, for letting the electronics engineers have the time and resources to develop what was perhaps the most important, ground-breaking electronic component created in the past century. µ