The Invention of the Processor

Processors were starting to be made around the 1960s with 10 to a few hundred transistors on medium scale Integrated Circuits. They were put onto printed circuit boards and were not very powerful. During the 1960s and 1970s NASA used what they called The Apollo Guidance Computer processor whose only logic elements were three-input NOR gates (you will learn about those later). When microprocessors started to be used widely, other types of computers became obsolete due to increase in efficiency, decrease in size, and they were much more reliable.

Intel was a leader in Microprocessor technology. They usually made microchips for calculators but in 1971, they were hired by BUSICOM to make a chip for a new line of calculators. They convinced BUSICOM to let them start designing a new chip that itself, was a mini computer. This chip was called the 4004 (picture on the homepahe) and consisted of 2300 transistors etched into its silicon base. This chip was 1/16 by 1/12 inches. It was as powerful as the 60 ton ENAIC that was constructed in 1946. It is amazing that in only 25 such a big improvement in Microprocessor technology was made.