Functional Components of Computer and Their Inter Connection

Functional Components of Computer and Their Inter Connection: Computers follow IPO cycle i.e., input-process- output cycle. Regardless of type and size of computer, all the computers has four main functional components:

  1. Input Unit
  2. Memory
  3. Central Processing Unit
  4. Output Unit


functional components of computer


Input Unit:

The input unit is used to link the external environment with the computer system: Data and instructions are entered into a computer through input devices.

An input unit takes the input and converts it into binary form so that it can be understood by the computer. This transformation is accomplished by units called input interfaces.

Some popular input devices are:

  • Keyboard
  • Mouse
  • Joystick
  • Punched cards
  • Optical mark reader.

Check these input devices:

The basic functions performed by input unit are:

  • It accepts (or reads) the instructions and data from the out side world.
  • It converts the instructions and data in computer acceptable form.
  • It supplies the converted instructions and data to computer system for further processing.


Output Unit:

The output devices receive results and other information from the computer. It takes the output and converts it into human acceptable form so that it can be understood by the outside world. Hence it links the computer with the external enviornment. These devices are required to deliver results to the user of the computer system. These units provide machine to man communication.

Some of the popular output units are:

  • Monitor
  • Printer
  • Plotter

Check out these output devices:

An output unit, therefore, performs the following functions:

  • It accepts the result produced by the computer into binary code.
  • It converts the coded data results to human acceptable form.
  • It supplies the converted results to the outside world.



The control unit and the arithmetic unit of a computer system are jointly known as central processing unit (CPU).

The CPU is the controlled center for a computer. It guides, directs and governs its performance. Therefore it is also known as the Brain of the Computer.

In the computer all the major calculations and comparisons are made inside the CPU and the CPU is responsible for activating and controlling the operations of other units of the computer system.

The major section of a CPU are:

  1. Arithmetic Logic Unit (ALU)
  2. Control Unit (CU)

ALU(Arithmetic Logic Unit):

The ALU performs the arithmetic and logic operations on the data as a result of the execution of decoded instructions. To be more precise, calculations are performed and all decisions are made in ALU.

It can perform all arithmetic calculations. e.g. addition, subtraction, multiplication, division etc. and logical operations (>, <, > =, < =, = =, ! =). The result of logical operations is either True or False.

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Control Unit:

The control unit controls and guides the interpretations, flow and manipulation of all data and information. The CU sends control signals until the required operations are done properly by ALU and memory.

Although control unit does not perform any actual processing on the data, the control unit acts as a central nervous system, for the other components of the computer system.

It manages and co-ordinates the entire computer system. It obtains instructions from the program stored in main memory, interprets the instructions, and issues signals, which cause other units of the system to execute them.


Storage Unit Functional Components of Computer:

In computers, data can be stored in devices called storage units. These storage units are often referred as memory devices. Storage Unit is also the storage functional components of computer.

The memory of computer is often called as main memory or primary memory and is third component of computer.

The data and instructions which are entered into the computer system through input units, have to be stored inside the computer, before the actual processing starts.

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Similarly, the results produced by the computer after processing must also be kept somewhere inside the computer system, before passed on the output units.

Moreover, the intermediate results produced by the computer, must also be preserved for ongoing processing. The storage unit is designed to fulfill all these needs.


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An aspiring BCA student formed an obsession with Computer/IT education, Graphic Designing, Fitness, YouTube and Blogging, and Helping Beginners to learn these skills and implement them in their life.

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