Introduction to Operating Systems
Introduction
A computer contains physical components such as the processor, memory, storage, keyboard, and monitor. It also needs software to manage these components and provide a way for people to use the computer. An operating system (OS) performs this central role.
This note explains what an operating system is, why it is needed, and how hardware, firmware, and software differ.
What Is an Operating System?
An Operating System (OS) is system software that manages a computer's hardware and software resources and provides a platform for users to interact with the computer.
The operating system acts as a link between the user and the computer hardware. A user can click an icon, type a command, or open an application; the OS coordinates the actions needed for the computer to respond.
For example, when you open a web browser, the operating system helps load the application into memory, schedule processor time, accept keyboard and mouse input, and display the browser on the screen.
The OS as a link between the user and hardware
User action
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Operating system manages the request
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Hardware performs the required operations
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Result is presented to the userThe OS manages interaction between software and hardware, helping the computer carry out tasks in an organised way.
Why Is an Operating System Needed?
An operating system is needed to manage computer resources and provide a usable, stable environment.
1. Resource management
The OS coordinates the computer's main resources:
- CPU (processor): Shares processor time between running tasks.
- Memory (RAM): Allocates memory to programs and manages its use.
- Storage: Helps organise files and folders on storage devices.
- Input and output devices: Coordinates devices such as keyboards, mice, monitors, and printers.
2. Organised operation
The OS helps programs and devices work together. It manages activities that may happen at the same time, such as playing audio while downloading a file and displaying a document.
3. Security and stability
Operating systems commonly provide user accounts, permissions, and other security controls. They also manage applications and hardware resources to help the computer operate reliably.
Key Idea: The operating system manages hardware and software resources and provides an environment in which users can run applications.
Hardware, Firmware, and Software
A computer system includes physical components and different kinds of instructions. Hardware, firmware, and software are related, but they do not mean the same thing.
Hardware
Hardware refers to the physical parts of a computer that can be seen and touched. Hardware carries out processing, storage, input, and output operations.
Examples include:
- CPU: Executes instructions and performs processing.
- RAM: Holds data and instructions currently being used.
- Hard disk or SSD: Stores files, programs, and other data.
- Keyboard and mouse: Allow users to provide input.
- Monitor: Displays visual output.
Hardware needs instructions from software to perform useful tasks.
Example: Keyboard and monitorA keyboard is hardware because it is a physical input device. A monitor is hardware because it physically displays information from the computer.
Firmware
Firmware is low-level software stored in a device's non-volatile memory, such as ROM or flash memory. It provides instructions that help the device operate and, in a computer, can help initialise hardware and start the operating system.
Examples include:
- BIOS/UEFI: Firmware used by many computers to initialise hardware and begin the boot process.
- Device firmware: Embedded instructions used by devices such as routers, printers, and keyboards.
Firmware is software, but it is closely associated with the operation of a particular device. It is generally stored so that its instructions remain available when the device is switched off.
Example: Router firmwareA router uses firmware to carry out built-in functions, such as managing network connections and providing its configuration interface.
Software
Software is a collection of programs and instructions that tell a computer what to do. Unlike hardware, software is not a physical component that can be touched.
Software is commonly divided into two broad categories.
1. System software
System software manages or supports the operation of the computer and provides services for application programs.
Examples include operating systems such as Windows, macOS, and Linux, as well as utility programs that help maintain or manage a computer.
2. Application software
Application software helps users perform particular tasks.
Examples include:
- Microsoft Office applications for creating documents, spreadsheets, and presentations.
- Google Chrome for browsing the web.
- Antivirus applications for detecting and responding to security threats.
Comparison: Hardware vs Firmware vs Software
| Feature | Hardware | Firmware | Software |
|---|---|---|---|
| Meaning | Physical computer components | Low-level instructions stored in a device | Programs and instructions used to perform tasks |
| Physical form | Can be seen and touched | Stored electronically in memory | Stored electronically and executed by a computer |
| Main role | Performs processing, storage, input, or output | Helps initialise or control a device | Manages system activities or helps users perform tasks |
| Examples | CPU, RAM, keyboard, monitor | BIOS/UEFI, router firmware | Windows, Linux, web browsers, office applications |
Firmware is a type of software, but it is usually designed for a specific device or low-level function. An operating system is system software that manages broader computer resources and provides services for applications.
How These Parts Work Together
Hardware, firmware, and software work together when a computer starts and when a user runs a program.
Computer is switched on
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Firmware helps initialise the hardware
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The operating system starts
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The OS manages hardware and system resources
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Application software runs
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The user interacts with the applicationThe exact startup sequence varies by device, but firmware can help prepare the system to start, while the operating system manages the computer during normal use.
Example: Opening a document- The user opens a document application.
- The operating system loads the application and allocates the resources it needs.
- The CPU executes instructions, and RAM holds the data currently in use.
- The application reads the document from storage.
- The operating system and display hardware help show the document on the monitor.
This example shows how software depends on the OS and hardware to carry out a task.
Exam-Focused Points
Key Idea: An operating system is system software that manages computer hardware and software resources and provides a platform for users to interact with the computer.
Key Idea: Hardware is physical, firmware is low-level software stored in a device, and software consists of programs and instructions.
Key Idea: BIOS/UEFI is an example of firmware, while Windows, macOS, and Linux are examples of operating systems.
Quick revision
- CPU: Processes instructions.
- RAM: Holds data and programs currently in use.
- Storage: Keeps files and programs for later use.
- Firmware: Helps a device operate and may initialise hardware during startup.
- Operating system: Manages resources and supports applications.
- Application software: Helps users perform specific tasks.
Summary
An operating system is essential system software that manages a computer's resources and connects user activities with the hardware operations needed to complete them. It helps manage the CPU, memory, storage, and input/output devices while providing an environment for applications.
Hardware consists of the physical components of a computer. Firmware is low-level software stored in a device, while software includes system programs and applications. These parts work together to make a computer usable.