Block Diagram of Computer System | Components & Functions Infographic on Block Diagram of Computer System. Central Processing Unit (CPU) of Computer System. The Central Processing unit is also called as brain or heart of a computer CPU is nothing but an electronic hardware device which carries or performs out all Block Diagram of Computer and its Various Components Block Diagram of Computer and its Various Componentsuter is an electronic device which performs tasks given by user with extremely fast speed and accuracy. The input device is used to input data into the computer system. Function of input unit: Block diagram of computer system - Computersciencementor Storage Unit: The Storage unit is also a part of a block diagram of computer. Storage unit or secondary storage unit is a non-volatile device that holds programs, files, documents. It provides facilities to store a large volume of data. CPU executes the data stored on storage devices indirectly.