Microprocessor Invented
In 1971, Intel released the 4004, widely regarded as the first commercially available microprocessor: a complete central processing unit etched onto a single chip of silicon. Packing the core logic of a computer into a fingernail-sized component made computing dramatically cheaper and smaller, and it set the stage for the personal computer, the embedded devices that now sit inside cars, appliances, and countless other machines, and much of modern digital life.
The background lay in the rapid progress of integrated circuits during the 1960s. Engineers had learned to place more and more transistors on a single chip, a trend later summarized in Gordon Moore's observation that component density doubled at regular intervals. Even so, computers were typically built from many separate chips or boards. In 1969, the Japanese calculator company Busicom approached Intel, then a young firm founded in 1968, to produce a set of custom chips for a line of calculators. Busicom's initial design called for a dozen or so specialized circuits.
Intel engineers, notably Ted Hoff, proposed a simpler and more flexible approach: a general-purpose processor that could be programmed to perform different tasks, supported by memory and input-output chips. Stanley Mazor helped refine the architecture, and Federico Faggin, who joined in 1970, led the silicon design and brought the chip to working form, with contributions from Busicom's Masatoshi Shima. The resulting 4004 was a 4-bit processor containing roughly 2,300 transistors, and it ran at a clock speed of a few hundred kilohertz. By modern standards it was extremely modest, but it could execute stored programs, which made one chip adaptable to many uses.
Intel later negotiated to regain the right to sell the chip to other customers, a decision that proved pivotal. It followed the 4004 with the 8-bit 8008 in 1972 and the more capable 8080 in 1974. Competing designs soon appeared from other firms, including Motorola and MOS Technology. Historians note that the 4004's claim to being first is qualified: other projects, such as a processor developed for a US Navy aircraft system and Texas Instruments' work, involved similar ideas, though many were classified or not sold commercially. Intel's chip is usually credited as the first general-purpose commercial microprocessor.
The consequences were profound. By the mid-1970s, hobbyists were building microcomputers around chips like the 8080, leading to machines such as the Altair 8800 and, soon after, products from Apple, Commodore, and others. In 1981, IBM's personal computer used an Intel processor from the same lineage, cementing a architecture that still shapes computing today. Meanwhile, microprocessors spread into calculators, cash registers, industrial controls, and eventually phones. The 4004 was a small chip, but it marked the moment when computing power began its long migration from institutions into everyday objects.