When we switch on a computer, the first thing that loads on the screen is the operating system. The operating system, often shortened to OS, is the most important software in a computer. It is the manager of the whole computer. It decides how the hardware, software, and the user will work together.
In this chapter, we will learn what an operating system is and what it does. We will study the main functions of an operating system and the different types of operating systems. We will also learn about the Windows desktop, the parts of a window, and how files and folders are organised on a computer. By the end of this chapter, you will be able to use an operating system confidently and understand how it keeps everything working.
An operating system is a set of programs that manages and controls all the resources of a computer. It is the first program that loads when a computer starts, and it stays in the background as long as the computer is on.
The operating system acts as an interface between the user and the hardware. An interface is a way of connecting two things. The operating system provides a friendly interface so that a user can easily give commands to the computer without understanding its complex internal parts.
Some popular operating systems are Microsoft Windows, macOS for Apple computers, Linux which is free and open-source, and Android which runs on most mobile phones.
Without an operating system, a computer is just a collection of hardware parts. The OS is like the head teacher of a school, who manages teachers, students, and all the activities in an orderly way.
The operating system performs many important jobs. The main functions are:
Booting the computer: When we switch on a computer, the operating system is loaded into the memory from the hard disk. This process of starting the computer is called booting. The OS checks that all parts are working and then shows the desktop.
Managing memory: The operating system manages the memory of the computer. It decides which programs will use which part of the memory and makes sure every program gets the memory it needs.
Managing hardware: The operating system controls all the hardware devices. When we type on the keyboard, move the mouse, or send a file to the printer, the OS coordinates these devices through their drivers.
Managing files: The operating system organises data in files and folders. It lets us create, copy, move, rename, and delete files. It keeps track of where each file is stored.
Providing security: The operating system protects the computer from unauthorised users. It asks for a username and password before letting someone log in.
Running applications: The operating system allows application software to run. When we open a game or a word processor, the OS loads it and manages its working.
Operating systems can be classified in different ways.
Single-user and multi-user operating systems: A single-user operating system allows only one user to use the computer at a time, like on a home personal computer. A multi-user operating system allows many users to use the same computer at the same time, like in a bank or a school computer lab.
Single-tasking and multitasking operating systems: A single-tasking OS can run only one program at a time. A multitasking OS can run several programs at the same time, like listening to music while writing in Word. Windows is a multitasking OS.
Real-time operating systems: These are used in machines that must respond instantly, such as in a car's braking system or a pacemaker. They react to events in a fraction of a second.
Mobile operating systems: These are designed for mobile phones and tablets. Android and iOS are examples. They use touchscreens and are optimised for small devices.
Graphical operating systems: These provide a graphical user interface (GUI) with windows, icons, and menus that we can click with a mouse. Windows and macOS are graphical operating systems. Older systems that used only text commands are called command-line operating systems, like MS-DOS.
When the Windows operating system starts, we see the desktop. The desktop is the first screen that appears. It is like a real tabletop where we can place our work.
The important parts of the Windows desktop are:
Icons: Icons are small pictures on the desktop. Each icon represents a program, a file, or a folder. Double-clicking an icon opens the item it represents. The Recycle Bin is an icon that holds deleted files.
Taskbar: The taskbar is the bar at the bottom of the screen. It contains the Start button, the icons of running programs, and the clock. The Start button opens the Start menu, from which we can open all programs.
Start button: The Start button is usually at the left end of the taskbar. Clicking it opens the Start menu, where we can find all installed programs, search for files, and shut down the computer.
Wallpaper: The wallpaper is the background picture of the desktop. We can change it to any picture we like.
Shortcuts: A shortcut is an icon that points to a program or file. Clicking a shortcut opens the item quickly without searching for it.
The operating system stores all data as files. A file is a collection of information given a name. A file can be a text document, a picture, a song, or a program. The name of a file has two parts separated by a dot: the name and the extension. The extension tells us the type of the file. For example, in "story.txt", "story" is the name and ".txt" is the extension.
Some common file extensions are: - .txt - a simple text file - .docx - a Word document - .xlsx - an Excel spreadsheet - .pptx - a PowerPoint presentation - .jpg - a picture file - .mp3 - a music file - .mp4 - a video file
A folder is like a box or a drawer in which we keep files and other folders. Folders help us organise our files neatly. We can make a folder called "My School Work" and keep all our project files inside it. A folder inside another folder is called a subfolder.
To keep files safe and easy to find, we should give them clear names and place them in the correct folders.
In a graphical operating system, every open program appears in a window. A window is a rectangular area on the screen. Each window has common parts:
Title bar: The bar at the top of the window that shows the name of the program or file.
Minimise button: This button shrinks the window to the taskbar. The program keeps running but is hidden.
Maximise button: This button makes the window fill the whole screen.
Close button: This button closes the window and stops the program.
Menu bar: The bar below the title bar with menus like File, Edit, and View.
Scroll bar: The bar on the side or bottom that we drag to see parts of the screen that are hidden.
A computer should always be shut down properly, never by directly switching off the power. In Windows, we click the Start button, then click the Power option, and then choose Shut Down. The operating system then saves all the work, closes all programs safely, and switches off the computer. This keeps the computer healthy and prevents data loss.
| Part of Desktop | Function |
|---|---|
| Icon | Small picture representing a program or file |
| Taskbar | Bar at the bottom with Start button and running programs |
| Start button | Opens the Start menu to run programs |
| Wallpaper | Background picture of the desktop |
| Recycle Bin | Holds deleted files |
| File Extension | Type of File |
|---|---|
| .txt | Simple text file |
| .docx | Word document |
| .xlsx | Excel spreadsheet |
| .jpg | Picture file |
| .mp3 | Music file |
In this chapter, we learned that the operating system is the most important software that manages all the resources of a computer. We studied its main functions, including booting, managing memory and hardware, organising files, and providing security. We learned about different types of operating systems, from single-user and multi-user systems to graphical and mobile operating systems. We explored the Windows desktop, understanding icons, the taskbar, the Start button, and the wallpaper. We also learned how files and folders are organised and how file extensions tell us about the type of a file. The operating system is the bridge between us and the computer, and knowing how it works makes us confident and careful users of technology.