The Central Processing Unit is the computer system. It carries out arithmetic operations and controls input, output and storage units. CPU functions can be classified into two categories: Co – coordinating all computer operations and performing arithmetic and logical operations on data.
The CPU has three main components: Arithmetic and Logic Unit, Control Unit and Registers. The arithmetic and logic unit is the CPU part where computations take place. It has circuits that perform arithmetic operations on data that is received from the memory and are capable of comparing numbers. The control unit controls and directs the activities of the computer system. In short, it interprets the instructions derived from the main computer memory; send the control signals to devices that execute instructions. Registers are high-speed memories that store data for immediate processing.
The CPU is like a calculator, but very powerful. Its main function is to carry out arithmetic and logical operations on data. It is controlled by several software instructions. Initially, software instructions are held in secondary memory storage devices such as CD-ROM, hard disk, magnetic tape or floppy disk. These instructions are then loaded into the main memory of a computer.