Central Processing Unit
What is a Central Processing Unit?
The form, design and implementation of CPUs have changed over the course of their history, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, hardware registers that supply operands to the ALU and store the results, and the control unit that fetches instructions from the main memory, and decodes and executes them while relying on the ALU and registers as necessary to perform decomposed operations.
Most modern CPUs are microprocessors, meaning they are contained on a single integrated circuit (IC) chip. An IC that contains a CPU may also contain memory, peripheral devices, and other components of a computer; such devices are variously called microcontrollers or systems on a chip (SoC). Some computers have multi-core processors with two or more CPUs (which are then called "cores") within a single chip. On the other hand, array processors or vector processors have multiple processors that operate in parallel, with no one unit considered central.