Introduction to Operating System – JSS2 Computer Hardware & GSM Repair Lesson Note (First Term)

What are the functions of an operating system?

The OS has three main jobs: communication, resource management and storage.

1. Communication: it lets you talk to the computer. When you click an icon, the OS tells the hardware to open that file.
2. Resource management: it decides which app uses the CPU (the “brain”) and the memory (RAM) at any time.
3. Storage (file management): it keeps track of where files are saved on the hard drive so you can find them later.

Other things an OS does

• Runs programs: it starts and stops apps when you open or close them.
• Controls devices: it works with the keyboard, mouse, printer and screen.
• Gives security: it can protect the device with passwords and user accounts.

What are the types of operating system?

Operating systems are grouped by the device they run on, mainly desktop (computer) systems and mobile (phone) systems.

What are desktop operating systems?

Desktop operating systems run on desktop and laptop computers.

1. Microsoft Windows

Windows is the most popular OS for desktop and laptop computers.

• Owner: Microsoft.
• Versions: you probably use Windows 10 or Windows 11 in the computer lab.
• Best for: offices, schools and gaming.
• Feature: it uses a GUI, so you click icons and buttons with a mouse instead of typing commands.

2. Linux

Linux is an open source operating system, which means it is free for anyone to use or change.

• Open source: the program code is open for people to read, copy and improve.
• Best for: servers, supercomputers and people who like to write code.
• Fact: Linux runs many web servers and some smart devices.

Another desktop example

• macOS: the OS on Apple Mac computers, made by Apple.

What are mobile operating systems?

Mobile operating systems are made for smartphones and tablets, and they work with touchscreens.

3. Android

Android is the most used mobile OS in the world.

• Owner: Google.
• Best for: variety, because many companies such as Samsung, Tecno and Infinix use it, so there are many phones to choose from.
• Feature: it is easy to customise, so you can change how your home screen looks.

4. iOS

iOS is the OS found only on devices made by Apple.

• Devices: iPhone and iPad.
• Best for: ease of use and security.
• Feature: it runs smoothly, and the App Store checks apps for safety before people can download them.

What is the difference between a GUI and a command line?

A GUI (Graphical User Interface) lets you use pictures, icons and menus to control a computer.

A command-line interface (CLI) makes you type written commands to control a computer.

How do the common operating systems compare?

Evaluation

1. Why can’t we use a computer that has no operating system?
2. If you are a programmer who wants to change how the OS works for free, which one would you choose?
3. Which mobile OS is owned by Google?
4. True or False: You can install iOS on a Samsung phone. Explain your answer.
5. List the three main functions of an operating system.

Assignment

Check the phone of a parent or guardian, or a computer in the lab. Write down the device, the OS it uses and the owner of that OS.