GCE O/L ICT Lesson 5: Everything You Need to Know About Operating Systems

In the world of ICT, the Operating System (OS) acts as the “soul” of the computer. Without it, your hardware is just a collection of metal and plastic. For GCE O/L ICT students in Sri Lanka, Lesson 5 is a critical unit that covers how a computer manages its resources and interacts with you, the user.

This post combines detailed exam-targeted notes with interactive learning tools available at SchoolICT.net.

1. What is an Operating System?

An Operating System is the primary software that manages computer hardware, software resources, and provides common services for computer programs.

Key Exam Fact: When you turn on a computer, the BIOS (Basic Input/Output System) performs a power-on self-test and then loads the OS from the hard drive into the RAM. This process is called Booting.

2. Core Functions of an OS

The OS wears many hats. Here are the five most important functions you must remember for your exam:

1. Process Management: The OS decides which program gets to use the CPU, for how long, and in what order (Scheduling).
2. Memory Management: It allocates space in the RAM for open applications and clears that space when you close them.
3. File Management: It creates a structured system (Folders and Files) for storing, retrieving, and naming your data.
4. Hardware/Device Management: It uses Device Drivers to communicate with peripherals like printers, scanners, and mice.
5. Security and User Interface: It provides a way for you to interact with the computer (like Windows or icons) and protects your data with passwords.

3. Classifying Operating Systems

Operating systems are categorized based on how they handle users and tasks:

• Single-user: Designed for one person at a time (e.g., MS DOS, Windows 10/11 for personal use).
• Multi-user: Allows multiple users to access the same system simultaneously (e.g., Linux, Windows Server).
• Multi-tasking: Allows the computer to run more than one program at the same time (e.g., listening to music while typing a document).

4. OS Utility Tools

Utilities are small programs within the OS that help maintain and optimize the computer.

• Formatting: Preparing a storage device (like a USB or Hard Drive) to store data. Warning: This deletes all existing data!
• Disk Defragmentation: Reorganizing scattered fragments of files on a hard drive so the computer can read them faster.
• Disk Cleanup: Identifying and removing unnecessary files to free up storage space.

5. Interactive Tool: File Size Converter

A common topic in Lesson 5 is understanding data storage units. Our OS Learning Tool includes a File Size Converter to help you practice conversions between Bytes, KB, MB, GB, and TB.

Remember the Scale:

• 1024 Bytes = 1 Kilobyte (KB)
• 1024 KB = 1 Megabyte (MB)
• 1024 MB = 1 Gigabyte (GB)
• 1024 GB = 1 Terabyte (TB)

6. Exam Preparation & Resources

To help you ace your GCE O/L ICT exam, we have provided comprehensive resources on our platform:

• Structured Questions: Practice writing answers for OS-related scenarios.
• Online Quiz: Test your knowledge with MCQ sessions.
• Downloadable PDF: Get the full Lesson 5 target notes for offline study.

Visit the full lesson and tools here:

• Lesson 5: Operating System Notes
• Lesson 5: Interactive OS Learning Tools