Intel’s 4004 microprocessor turns 40

Intel 4004 Microprocessor Schematic

Today marks the 40th anniversary of the Intel 4004, generally recognised to be the first commercially available microprocessor and the start of a revolution that would change the face of the world forever.

Nowadays, microprocessors are everywhere: phones, laptops, TVs are a given – but they’re also found in watches, microwaves, washing machines and fridges. They’re the digital brains behind modern technology as a whole and often feature hundreds of millions of transistors.

The Intel 4004 was a different matter. Back in 1968, Intel was approached by the Nippon Calculating Machine Corporation for a design of 12 custom chips for its upcoming Busicom 141-PF printing calculator. Seeing – and hating – inefficiency, the hackers at Intel proposed an alternative solution: reducing the design to just four chips, including a general-purpose programmable microprocessor.

The MCS-4 family would include a read-only memory chip for the calculator’s application code, a random-access memory chip for holding data, a shift-register chip for handling IO and – last but by no means least – the Intel 4004 microprocessor.

Realising that the hackers in the engineering department were on to something, Intel’s beancounters offered the Nippon Calculating Machine Corporation a reduced rate on the chips if Intel could retain ownership of the microprocessor design. The company agreed, and the Intel 4004 became the first general-purpose microprocessor to hit the open market, advertised to the public for the first time on November the 15th 1974 in Electronic News.

Produced on two-inch silicon wafers – significantly smaller than the 12-inch wafers in common use today – the Intel 4004 had a mere 2,300 transistors spaced 10 microns – or 10,000 nanometres apart. By contrast, Intel’s current generation of processors hold around 530 million transistors at a spacing of 32nm to 28nm.

The sheer scale of the growth seen in the world of integrated circuits in 40 years is staggering, but hackers still have plenty of room to innovate. “The sheer number of advances in the next 40 years will equal or surpass all of the innovative activity that has taken place over the last 10,000 years of human history,” Intel chief Justin Rattner claimed during the company’s celebrations today.

To help celebrate the 4004’s success, Intel has produced the below video which should prove of interest to those who marvel at microprocessor design.