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

An operating system is the main program that manages a computer’s hardware and runs all other programs.

• Position: it sits between the hardware (the physical parts) and the programs you use every day.
• Role: it works like a manager that makes all parts of the computer work together.
• Without it: a computer cannot start or run programs, like a car with no driver.

Behavioural objectives

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

1. state the main jobs of an operating system;
2. name five operating systems and say where each is used;
3. describe the four parts of an operating system;
4. list the steps a computer follows when it starts up;
5. explain the difference between RAM and storage.

What are the main jobs of an operating system?

An operating system has five main jobs: it provides an interface, manages files, manages resources, gives protection and handles networking.

• User interface: it lets you talk to the computer through the screen, keyboard and mouse.
• File management: it keeps your files safe and organised.
• Resource management: it gives each program the time and memory space it needs to run.
• Protection: it guards the computer from harmful programs and from people who should not use it.
• Networking: it helps the computer connect to other computers and the internet.

What are the types of operating system?

There are five common operating systems: Windows, macOS, Linux, Android and iOS.

• Windows: made by Microsoft and widely used on home and office computers, for example Windows 10 and Windows 11.
• macOS: made by Apple and found on Apple computers such as the MacBook, known for being easy to use.
• Linux: free for anyone to use and change, and common on servers. Ubuntu and Fedora are versions of Linux.
• Android: used on many phones and tablets, and based on Linux.
• iOS: made by Apple and used on the iPhone and iPad.

What are the parts of an operating system?

An operating system has four main parts: the kernel, device drivers, the user interface and the file system.

• Kernel: the heart of the operating system, which talks directly to the hardware and runs all the time.
• Device drivers: small programs that help the operating system talk to parts such as printers, screens and keyboards.
• User interface: what you see on the screen, which is how you give instructions to the computer.
• File system: it keeps track of where files are saved and helps you find them.

What are the kinds of user interface?

• Command-line interface: you type text commands to give instructions.
• Graphical user interface (GUI): you use pictures (icons), windows and buttons that you click or tap.

How does a computer start up?

Start-up, also called booting, is the set of steps a computer follows from switching on until you can use it.

1. The computer checks that its parts are working.
2. It finds the operating system on the storage drive.
3. The operating system loads into memory (RAM).
4. The operating system starts the services it needs.
5. The login screen appears.
6. After you log in, you can start using programs.

How does the operating system manage memory?

Memory management means the operating system decides what goes into RAM and what stays in storage.

• RAM (Random Access Memory): fast memory that loses its contents when the power goes off. Running programs are kept here.
• Storage (hard drive or SSD): memory that keeps your files even when the power is off, but is slower than RAM.

What is virtual memory?

Virtual memory is the use of storage space to hold data when RAM is full.

1. RAM fills up as more programs run.
2. The operating system moves some data from RAM to storage.
3. This frees RAM space for the programs that need it now.

How does the operating system manage processes?

A process is a program that is running, and the operating system controls every process.

• Starting and stopping: it starts processes and ends them when they finish.
• CPU time: it gives each process a turn to use the CPU (Central Processing Unit).
• Separation: it makes sure processes do not interfere with each other.
• Communication: it lets processes pass information to each other when needed.

What security features does an operating system have?

Security features are the tools an operating system uses to protect the computer and its users’ information.

• Passwords: they are asked for before a person can use the computer.
• User accounts: each user’s files are kept separate from other users’ files.
• Program checks: the system checks whether programs are safe to run.
• Protection tools: built-in tools warn about or block harmful programs and websites.
• Updates: the system updates itself to fix security problems.

Why does the operating system matter?

The operating system you use affects five things about your computer.

• Programs: it decides which programs you can run.
• Ease of use: it shapes how easy the computer is to use.
• Safety: it affects how safe your information is.
• Speed: it affects how fast the computer works.
• Hardware: it decides which devices you can connect.

How do people choose an operating system?

• Habit: the one they are used to.
• Work needs: the one their work requires.
• Purchase: the one that comes with the computer they buy.

What is the future of operating systems?

Operating systems keep changing to work with new technology.

• Cloud computing: using programs and storage over the internet.
• Voice commands: controlling the computer by speaking, with virtual assistants.
• Artificial intelligence: computer systems that perform tasks that normally need human thinking.
• Virtual reality: computer-made worlds that you view through special headsets.
• Connected devices: more devices in homes and offices that must work together.

Evaluation

1. What is an operating system?
2. State three jobs of an operating system.
3. Name the company that makes Windows and the company that makes macOS.
4. What is the difference between RAM and storage?
5. What is a process?

Assignment

Write a short note that does three things: lists the steps a computer follows when it starts up in the correct order, names the four parts of an operating system with one sentence on each, and gives three security features of an operating system.