The Hardware Component of a Computer System – JSS2 Computer Studies Lesson Note (First Term)

Computer hardware is the physical parts of a computer that you can touch, pick up, hold and move around.

Behavioural objectives

By the end of the lesson, students should be able to:

1. define computer hardware;
2. list the components of computer hardware;
3. give examples of input devices and output devices;
4. state the two types of output device;
5. state the functions of the storage device, the arithmetic logic unit and the control unit.

What is computer hardware?

Hardware is any computer part you can physically touch, pick up, hold and move around.

• Meaning: hardware is the physical parts that make up the computer.
• Examples: keyboard, mouse, monitor, printer and hard disk drive.

What is the difference between hardware and software?

Hardware is the physical part of a computer. Software is the set of programs that tells the hardware what to do, and you cannot touch it.

What are the components of computer hardware?

There are five main components of computer hardware: input device, output device, storage device, arithmetic logic unit and control unit.

1. Input device: enters data and programs into the computer.
2. Output device: gives out processed information.
3. Storage device: keeps data and instructions.
4. Arithmetic logic unit (ALU): does calculations and comparisons.
5. Control unit (CU): directs all the operations of the computer.

• Note: the arithmetic logic unit and the control unit together make up the central processing unit (CPU).

What is an input device?

An input device is a piece of hardware the user uses to enter data and programs into the computer system for processing.

Input devices are divided into two types:

• Manual input devices: the user operates them by hand, for example the keyboard and the mouse.
• Automatic input devices: they collect data with little or no typing, for example the scanner and the sensor.

What are examples of input devices?

What is an output device?

An output device is a piece of hardware that sends usable processed information out of the computer.

What are examples of output devices?

What are the types of output device?

There are two types of output device: temporary output devices and permanent output devices.

• Temporary output devices: the output disappears when the device is switched off or changes, for example monitors, which constantly refresh the image on the screen.
• Permanent output devices: the output stays, for example printers, which output information onto paper as a hard copy.

What is a storage device?

A storage device is a piece of hardware that stores data and instructions before and after processing.

• Hard disk drive: the main storage inside most computers.
• Compact disk drive: reads and writes data on CDs.
• Flash drive: a small portable device that plugs into a USB port.
• Memory card: a small card used in phones and cameras.

What does the arithmetic logic unit do?

The arithmetic logic unit (ALU) performs arithmetic and logical operations on data.

• Arithmetic operations: addition, subtraction, multiplication and division.
• Logical operations: comparisons such as greater than, less than and equal to.

What does the control unit do?

The control unit (CU) controls all operations of the computer, such as input, processing and output.

• It takes care of the step-by-step processing of all operations inside the computer.
• It tells the other hardware parts when and what to do.

How do the hardware components work together?

The hardware components work together in a fixed order to turn data into information.

1. An input device enters the data.
2. The storage device holds the data and instructions.
3. The control unit directs each step.
4. The arithmetic logic unit processes the data.
5. The results are stored.
6. An output device gives out the information.

Evaluation

1. What is computer hardware?
2. List the five components of computer hardware.
3. Name five input devices and four output devices.
4. State the two types of output device and give one example of each.
5. What is the function of the control unit?

Assignment

Write short notes on the storage device and the arithmetic logic unit. In your answer:

• explain the function of the storage device and give two examples;
• state two operations performed by the arithmetic logic unit.