Functions of Operating System – JSS2 Computer Studies Lesson Note (First Term)

An operating system (OS) is the software that manages a computer’s hardware and runs other programs. Its functions include accepting input, sending output to devices, recognising peripheral devices, managing files and folders, sharing memory, loading and running applications, managing security, handling system problems and moving data to and from the hard disk.

Behavioural objectives

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

1. state the functions of an operating system;
2. explain how the operating system handles input and output;
3. describe how the operating system manages files, folders and memory;
4. give an example of how the operating system manages security and handles system problems.

What is an operating system?

An operating system is system software that controls the hardware and lets the user and application programs work with the computer.

• Hardware: the physical parts of the computer, such as the keyboard, monitor and hard disk.
• Application software: programs that do tasks for the user, such as word processing and spreadsheets.
• Operating system: the software that sits between the user, the applications and the hardware.
• Peripheral device: any device connected to the computer, such as a printer, pen drive or webcam.

What are examples of operating systems?

Where does the operating system sit in a computer?

The operating system sits between application software and the hardware.

What are the functions of an operating system?

An operating system has ten main functions, grouped below by the job each one does.

What does the operating system do with input and output?

• It accepts inputs: it takes input from devices such as the mouse and keyboard.
• It sends outputs to the monitor or printer: it passes results to output devices such as the monitor and printer.

What does the operating system do with hardware?

• It recognises peripheral devices: it detects devices such as external hard disks, pen drives and webcams.
• It makes sure the needed software is installed: the software that lets the hardware run must be present.
• It lets applications communicate with hardware: word processing and spreadsheet programs use the hardware through the operating system.

How does the operating system manage files and folders?

• Naming: it lets the user give names to files and folders.
• Creating: it lets the user make new files and folders.
• Moving: it lets the user shift files and folders from one place to another.
• Finding: it helps the user search for a file or folder.
• Deleting: it lets the user remove files and folders no longer needed.

How does the operating system share memory?

• Assigning memory: it decides how much memory each task gets.
• Moving data: it moves data in and out of memory as tasks need it.
• Efficient sharing: several tasks can then use the memory without clashing.

How does the operating system run applications?

• Loading: it brings application software into the computer’s memory.
• Running: it lets programs such as word processors and spreadsheets work.

How does the operating system manage security?

• Passwords: it allows passwords to be added or changed.
• Protection: only users who know the password can use the protected account.

How does the operating system handle system problems?

• Identifying problems: it finds faults in the computer system.
• Alerting the user: it shows a warning message so the user can act.

How does the operating system move data to and from the hard disk?

• Saving: it moves processed data or information to the hard disk.
• Retrieving: it brings data back from the hard disk when it is needed.

What is a quick summary table of the functions?

What does the operating system do when a printer is jammed?

The operating system stops the print job and warns the user.

1. The user sends a document to the printer.
2. The printer jams and cannot print.
3. The operating system identifies the problem.
4. It stops the print job.
5. It shows a warning message to alert the user.

Evaluation

1. What is an operating system?
2. List five functions of an operating system.
3. Name two peripheral devices that the operating system recognises.
4. Explain what the operating system does when a printer is jammed.
5. How does the operating system share system memory?

Assignment

Write down four ways in which the operating system manages files and folders. Then explain, with one example, how the operating system manages system security.