What is a microprocessor?

Putting the components (read/write memory, ALU, and control unit) together results in a digital device that is typically called a processor. If minimal memory is used, and all the necessary components are contained on a single integrated circuit, it is called a microprocessor. When combined with the necessary bus-control support circuitry, it is known as a Central Processing Unit, or CPU. The first microprocessor was the Intel 4004, introduced in 1971. All it could do was add and subtract, and it could only do that 4 bits at a time. But it was amazing that everything was on one chip. Prior to the 4004, engineers built computers either from collections of chips or from discrete components ( transistors wired one at a time). The 4004 powered one of the first portable electronic calculators.