Functional Units of Computer | Computer Architecture

YASH PAL,

Functional Units of a Computer – A computer in its simplest form comprises five functional units, namely the input unit, the output unit, the memory unit, the arithmetic & logic unit, and the control unit.

Functional units of computer
Functional Units of Computer

Functional Units of a Computer

  1. Input Unit
  2. Output Unit
  3. Storage Unit
  4. Arithmetic Logical Unit
  5. Control Unit

Input Units

The input unit connects the external environment with the internal computer system. It provides data and instructions to the computer system. Commonly used input devices are keyboard, mouse, magnetic tape, joysticks, and microphones, etc. The input unit performs the following tasks.

  1. Accept the data and instructions from the outside environment.
  2. Convert it into machine language.
  3. Supply the converted data to the computer system.

Output Units

It connects the internal system of a computer to the external environment. It provides the results of any computation or instructions to the outside world. Some output devices are printers, monitors, plotters, Plotters, Projectors, speakers, etc.

Storage Unit

This unit holds the data and instructions. It also stores the intermediate results before these are sent to the output devices. It also stores the data for later use. The storage unit of a computer system can be divided into two categories:

  1. Primary Storage: This memory is used to store the data which is being currently executed. It is used for temporary storage of data. The data is lost, when the computer is switched off so, its volatile memory. RAM is used as primary storage memory.
  2. Secondary Storage: The secondary memory is slower and cheaper than primary memory. It is used for permanent storage of data. Commonly used secondary memory devices are hard disk, CD etc.

Arithmetic Logical Unit

All the calculations are performed in ALU of the computer system. The ALU can perform basic operations such as addition, subtraction, multiplication, division etc. Whenever calculations are required, the control unit transfers the data from storage unit to ALU. when the operations are done, the result is transferred back to the storage unit.

Control Unit

It controls all other units of the computer. It controls the flow of data and instructions to and from the storage unit to ALU. Thus it is also known as central nervous system of the computer.

CPU – CPU is the Central Processing Unit of the computer. The control unit and ALU are together known as CPU. CPU is the brain of computer system. It performs following tasks:

  1. It performs all operations.
  2. It takes all decisions.
  3. It controls all the units of computer.
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