Module 1 – Computer Essentials

Lesson 2 – Operating System Basics (In-Depth)

An Operating System (OS) is the main software that controls the computer. It manages hardware, runs applications,
controls files and folders, provides security features and allows the user to interact with the device.
Without an OS, a computer cannot function.

This lesson explains the role of the OS, desktop environments, files and folders, multitasking, system settings,
updates, security and basic maintenance.

Learning outcomes

By the end of this lesson you should be able to:

• Explain what an operating system does.
• Identify key parts of the desktop environment.
• Describe different user account types and login methods.
• Work with windows and applications using common controls.
• Use File Explorer / Finder to manage files and folders.
• Locate and change basic system settings.
• Understand updates, security features and power options.
• Outline backup, recovery, accessibility tools and simple maintenance tasks.

Quick warm-up

Think about your own device (laptop / phone / PC). Which of these are operating systems?

• Chrome
• Windows 11
• Android
• Word

1. What is an Operating System?

The Operating System controls how the computer works. It acts as a bridge between the user, the hardware and the applications.

The OS manages:

• Hardware – keyboard, mouse, storage, screen, CPU and other components.
• Software – applications and background processes.
• Files and folders – storing, organising and accessing data.
• User accounts – login, permissions and security.
• Memory and performance – allocating RAM to running applications.
• Peripheral devices – printers, scanners, webcams, Bluetooth devices and more.

Common operating systems include:

• Microsoft Windows 10 / Windows 11
• macOS
• Linux (Ubuntu, Mint, Debian)
• Android (mobile)
• iOS (mobile)

Check your understanding: OS or application?

Decide if each is an operating system or an application:

• Excel
• Linux
• iOS
• Outlook

2. The Desktop Environment

When you turn on a computer and log in, the OS loads the desktop.
This is the main screen you use to work with applications and files.

Typical desktop elements:

• Taskbar or Dock – shows running applications and quick shortcuts.
• Start Menu / Launcher – open apps, search for files and access settings.
• Desktop icons – shortcuts to files, folders or apps.
• Notification area – shows time, Wi-Fi, volume, battery and alerts.
• Search bar – quickly find apps, settings or documents.
• System tray – background applications such as antivirus or cloud sync.

3. Logging in and User Accounts

Operating systems allow multiple people to share one device while keeping their files and settings separate.

3.1 Types of accounts

• Administrator account – full control; can install software and change system settings.
• Standard user account – limited access; suitable for everyday use, helps prevent accidental system changes.
• Guest account – temporary access with limited features (not always available).

3.2 Login methods

• Password
• PIN (short numeric code)
• Fingerprint (biometrics)
• Face recognition
• Security key (physical device)

Strong passwords and separate user accounts help protect personal data and system settings.

Mini scenario – which account?

A child is using the family PC for homework and games. Which account type is usually safest for them?

4. Working with Windows and Applications

The operating system lets you open, move and switch between multiple applications.

4.1 Common window controls

• Minimise – hides the window but keeps the application running on the taskbar.
• Maximise – enlarges the window to full screen.
• Restore – returns the window to its previous size after maximising.
• Close – exits the application window.

4.2 Multitasking features

• Task View – shows all open apps and virtual desktops.
• Alt + Tab (Windows) – quickly switch between running applications.
• Split screen / Snap Assist – arrange two or more apps side by side.
• Virtual desktops – separate workspaces for different tasks (for example, one for study, one for personal use).

5. File Explorer / Finder

Every operating system includes a file management tool:

• Windows: File Explorer
• macOS: Finder
• Linux: Files / Nautilus (or similar)

Common folder locations:

• Documents – personal files such as letters, reports and coursework.
• Downloads – files saved from the internet or email.
• Pictures – images and screenshots.
• Music and Videos – media folders.
• This PC / Computer – shows drives, storage devices and connected media.

5.1 Basic file and folder operations

• Create new folders to organise files.
• Copy, move, rename and delete files and folders.
• Use clear, meaningful file names (for example, Invoice_March_2025.docx).
• Recognise common file types such as .docx, .pdf, .jpg and .xlsx.

6. System Settings and Control Panel

Settings allow you to customise and control how your device behaves. In Windows 10/11 most options are found in the
Settings app, with some advanced tools still in the Control Panel.

Key settings include:

• Display settings – resolution, brightness and multiple screens.
• Network settings – Wi-Fi, Ethernet and mobile hotspot.
• Sound settings – speakers, microphone and audio output devices.
• Personalisation – wallpapers, themes and colours.
• Accessibility – text size, magnifier and screen reader tools.
• Update and Security – Windows Update, antivirus options and firewall.
• Storage settings – view drive space and manage temporary files.

7. Updates and Security

Operating systems must be kept up to date for security and performance.

7.1 Types of updates

• Security updates – protect against viruses, malware and vulnerabilities.
• Feature updates – add new tools and improvements.
• Driver updates – ensure hardware such as printers and graphics cards works correctly.

7.2 Security features

• Firewall – monitors network traffic for suspicious activity.
• Antivirus software – scans for viruses and other malware.
• User Account Control (UAC) – asks for permission before major system changes.
• Encryption – protects data stored on the drive (for example, BitLocker on Windows).

Keeping your OS updated is one of the most important steps in protecting your computer.

8. Power Options

Operating systems include several ways to manage power and protect your work:

• Shut down – closes all programmes and turns the computer off safely.
• Restart – closes everything and reloads the OS, often used after updates.
• Sleep – low-power mode that keeps work open for a quick resume.
• Hibernate – saves the current state to disk and powers off (not available on all systems).
• Lock – secures your account while you are away from the device.

9. Backup and Recovery

Operating systems provide tools to protect your files from loss or damage.

• File History / Time Machine – automatically back up personal files to another drive.
• System Restore – return the computer to an earlier working state without affecting most personal files.
• Cloud backups – use services such as OneDrive, iCloud or Google Drive to store copies online.
• External backups – copy important files to a USB drive or external hard drive.

10. Accessibility Features

Accessibility tools assist users with visual, hearing or mobility challenges.

• Magnifier – zooms in on parts of the screen.
• High-contrast mode – improves visibility of text and icons.
• On-screen keyboard – allows typing with a mouse or touch.
• Narrator / VoiceOver – reads text on the screen aloud.
• Speech recognition – control the computer with voice commands.
• Sticky Keys and Filter Keys – help users who find keyboard combinations difficult.

11. Basic Computer Maintenance

Simple maintenance tasks help keep your computer running smoothly.

• Use Disk Cleanup or Storage Sense to remove temporary files.
• Check Task Manager or Activity Monitor to see which apps use the most CPU or memory.
• Uninstall software that you no longer use.
• Install recommended updates for the operating system and applications.

12. Practical Activity

Try these tasks on your own computer or a training machine:

• Log in to your operating system and open the Settings menu.
• Check your account type (Administrator or Standard User).
• Open three applications and practise switching between them using Alt + Tab (or Command + Tab on macOS).
• Open File Explorer or Finder and locate the Documents, Pictures and Downloads folders.
• Change the desktop background using the Personalisation or Appearance settings.
• Turn on Magnifier or High Contrast mode and test accessibility tools.
• Check for operating system updates using Update and Security (or similar).
• View your device’s storage usage in the Storage settings and note how much free space is available.