Introduction to Computer System

In today's age of information, computer systems have become a necessity for everyone. A modern digital age student cannot even imagine life without a computer/smartphone, internet, social media, instant messaging, playing music & movies on the go and so on. Even in other essential activities like withdrawal and deposit of money through ATM, online shopping, e-learning, online ticket booking for movies, buses, railways and airlines or searching information on the internet. In short, the computer has become an integral part of our lives.

A computer system is a digital electronic device that mainly performs four functions:

• Input
• Process
• Store
• Output

A computer system mainly comprises a central processing unit (CPU), memory, input/output devices and secondary storage devices.

Central Processing Unit (CPU)

CPU is also considered as the brain of a computer system. The Central Processing Unit (CPU) is made of three parts:

• Control Unit (CU)
• Arithmetic & Logic Unit (ALU)
• Primary Memory Unit

Control Unit (CU)

The control unit controls and coordinates the operation of the entire computer system. It gets instructions stored in the primary memory unit, interprets and execute them.

Arithmetic & Logic Unit (ALU)

The actual execution of Instructions in the Control Unit is performing here, in the Arithmetic & Logic Unit. Data stored in primary memory are moved several times in ALU before the entire processing is completed.

Primary Memory Unit

Before the execution, instructions and data which are fed in via the Input Unit are stored in Primary Memory or Main Memory.

Input Unit

Input devices are the devices used to take input from the external environment with the computer. Typical input devices are keyboard, mouse, graphics tablet, microphone, scanner, joystick, gamepad etc. The function of the input unit is to accept external data and programs, convert them into a form that the computer can understand and can be further processed.

Output Unit

After processing of data or information is completed, it is transferred to the Output Unit to give the result to the external world. Output Unit converts the processed result into the human-readable form. Typical output devices are monitor, printer, speaker, projector etc.