Operating Systems

This lesson covers the purpose and functions of an operating system (OS), a key topic in AQA and OCR GCSE Computer Science. You need to understand what an operating system does, why it is needed, and its core management functions.

---

What Is an Operating System?

An operating system is a piece of systems software that manages the computer's hardware and software resources and provides a platform for application software to run. Without an operating system, you would need to write low-level code to interact directly with every piece of hardware — an impractical task for everyday users.

Examples of operating systems:

• Microsoft Windows
• macOS (Apple)
• Linux (Ubuntu, Fedora, etc.)
• Android (mobile)
• iOS (Apple mobile)

---

The Purpose of an Operating System

The OS acts as an intermediary between the user, application software, and the hardware. Its main purposes are:

1. Provide a user interface so humans can interact with the computer.
2. Manage hardware resources (CPU, memory, storage, I/O devices).
3. Manage files and control access to stored data.
4. Manage security and user accounts.
5. Provide a platform for running application software.

---