Computer is a group of integrated parts that have common purpose of performing the operations, called the program, which being executed qualifies it to be called a system. 

Computer is basically made of:

                       (1)              Input Unit

(2)       Central Processing Unit(C.P.U)

(3)       Output Unit

(4)       Memory  


Fig: Block Diagram of Computer System


Input : An input is a device of computer which feed data to the computer.

C.P.U.(Central Processing Unit) : C.P.U. is a main part of computer which process the data into information. It is also known as brain of computer. 

Output : An output is a device of computer which display information for user. 
                ( A person who operate the computer is called user)

Memory : Memory is a data holding place of computer. 
                                                   
                                              Types of Memory

There are two types of memory. They are :
                                                    1. Primary Memory 
                                                    2. Secondary Memory