Unit 3: Computer Software and Operating System
Complete Class 11 Computer Science Unit 3 notes covering software, operating systems, Windows, Linux, mobile operating systems and important NEB exam questions.
Welcome to Nepal eNotes. In this unit, you will learn about different types of computer software and the role of an Operating System (OS).
You will also study Windows, open-source operating systems such as Linux, mobile operating systems, and important exam-oriented questions.
- 3.1 Concept of Software
- 3.1.2 Categories of Software
- 3.2 Concept of Operating System
- 3.2.3 Functions of Operating System
- 3.2.4 Operating System Terminology
- 3.3 Windows Operating System
- Windows File & Device Management
- 3.4 Open Source Operating System
- Linux and UNIX
- Mobile Operating System
- Quick Revision
- Sample Board Exam Questions
What is Software?
Software is a set of instructions, programs or data used to operate a computer and perform specific tasks.
Unlike hardware, software cannot be physically touched. Software tells the computer hardware what work it should perform.
Hardware is the physical part of a computer, while software is the set of instructions that controls the hardware.
For example, Microsoft Word allows users to create documents, a web browser allows users to access websites, and games provide entertainment.
⚙ System Software
System software controls computer hardware and provides a platform for other programs.
Examples: Windows, Linux🛠 Utility Software
Utility software helps maintain and improve the computer system.
Examples: Antivirus, Disk Cleanup📝 Application Software
Application software helps users perform specific tasks.
Examples: MS Word, Photoshop, Chrome🌐 Web Based Software
Web-based software works through a web browser.
Examples: Google Docs, Gmail📱 Mobile Apps
Mobile apps are applications designed for smartphones and tablets.
Examples: WhatsApp, Instagram| Category | Purpose | Example |
|---|---|---|
| System Software | Controls hardware and provides a software platform | Windows, Linux |
| Utility Software | Performs maintenance tasks | Antivirus, Disk Cleanup |
| Application Software | Helps users complete specific tasks | MS Word, Photoshop |
| Web Based Software | Runs through a web browser | Google Docs, Gmail |
| Mobile Apps | Runs on smartphones and tablets | WhatsApp, Instagram |
What is an Operating System?
An Operating System (OS) is system software that acts as an interface between the user and computer hardware.
It manages computer resources and provides a platform where application software can run.
Windows, macOS, Linux, Android and iOS
Role of an Operating System
- Acts as an interface between the user and computer hardware.
- Manages processor time, memory and storage.
- Provides an environment for application software.
- Controls access to files, devices and system settings.
- Helps maintain security and system stability.
🧠 Process Management
Manages running programs and allocates processor time to each process.
💾 Memory Management
Allocates and releases RAM for different programs.
📁 File Management
Organizes, stores, retrieves and protects files and folders.
🖨 Device Management
Controls communication between the computer and connected hardware.
🔒 Security
Protects the computer from unauthorized access using passwords, permissions and accounts.
🖥 User Interface
Provides a graphical or command-line interface for users.
Multiprogramming
Multiprogramming allows several programs to stay in memory at the same time. The CPU switches between them so that CPU time is not wasted.
Multitasking
Multitasking allows users to work with multiple programs at nearly the same time.
For example, a user can browse the internet while listening to music.
Multiprocessing
Multiprocessing uses two or more processors or CPU cores so multiple processes can execute simultaneously.
Distributed Operating System
A distributed operating system manages several connected computers and makes them work as one unified system.
| Term | Main Idea |
|---|---|
| Multiprogramming | Several programs remain in memory to keep the CPU busy. |
| Multitasking | Users can run several applications seemingly at once. |
| Multiprocessing | Two or more CPUs/cores perform tasks simultaneously. |
| Distributed OS | Several networked computers function as one system. |
Multitasking = many tasks
Multiprocessing = many processors
GUI Based Operating System
A GUI or Graphical User Interface allows users to interact with a computer through visual elements such as icons, windows, menus and a mouse pointer.
Windows is a popular GUI-based operating system developed by Microsoft.
Main Features of Windows
- Desktop environment
- Start menu
- Taskbar
- Icons
- Multiple windows
- File Explorer
- Easy hardware support
Desktop and Window Environment
The desktop is the main screen that appears after the user logs in. Programs normally open inside separate windows.
- Minimize: Hides the window without closing the program.
- Maximize: Expands the window to fill the screen.
- Restore: Returns the window to its previous size.
- Close: Closes the program or window.
File Explorer
File Explorer is used to manage files and folders in Windows.
- Create Folder: Right-click → New → Folder
- Rename: Right-click → Rename or press F2
- Copy: Use Copy and Paste
- Move: Use Cut and Paste
- Delete: Select a file and press Delete
- Search: Use the File Explorer search box
Customizing Windows
- Change desktop wallpaper.
- Change themes and colors.
- Pin apps to Start or taskbar.
- Adjust display resolution.
- Change display scaling.
Installing and Removing Devices
Windows normally detects connected devices automatically and installs the necessary device driver.
Device Manager allows users to view connected hardware and update, disable or uninstall drivers.
Password and Privacy
- User accounts and passwords
- PIN login
- Windows Hello
- Fingerprint or facial recognition
- Privacy settings
- Administrator and Standard accounts
Control Panel
The Control Panel provides access to Windows system settings.
It can be used to manage programs, accounts, networks, devices and display settings.
System Tools
- Disk Cleanup – removes unnecessary files.
- Disk Defragmenter – reorganizes fragmented data.
- Task Manager – manages running programs and processes.
Windows Accessories
- Notepad
- Paint
- Calculator
An open-source operating system is an operating system whose source code is publicly available.
Users can view, modify and distribute the source code according to the applicable license.
| Open Source OS | Proprietary OS |
|---|---|
| Source code is publicly available. | Source code is kept private. |
| Users may modify the source code. | Users normally cannot modify source code. |
| Example: Linux | Examples: Windows, macOS |
UNIX
UNIX is an early operating system known for its stability, multi-user capabilities and security.
Linux
Linux is an open-source operating system inspired by UNIX.
It was originally created by Linus Torvalds in 1991.
Linux Distribution
A Linux distribution or distro is a complete operating system built around the Linux kernel together with other applications and utilities.
Ubuntu
A beginner-friendly Linux distribution used by students and developers.
Fedora
Known for introducing newer software and technologies.
Debian
Known for stability and used as the base for Ubuntu.
RHEL
Red Hat Enterprise Linux is widely used in business and enterprise environments.
A mobile operating system is software designed for smartphones, tablets and other mobile devices.
It manages mobile hardware and provides the platform on which mobile applications run.
| Mobile OS | Developer | Description |
|---|---|---|
| Android | Linux-based mobile operating system used by many manufacturers. | |
| iOS | Apple | Proprietary operating system used on iPhones. |
| HarmonyOS | Huawei | Operating system developed by Huawei. |
| KaiOS | KaiOS Technologies | Lightweight operating system used mainly on feature phones. |
⚡ Quick Revision – Unit 3
- Software is a collection of instructions and programs.
- Main software categories: System, Utility, Application, Web Based and Mobile Apps.
- An operating system acts as an interface between user and hardware.
- Major OS functions: process, memory, file, device, security and user-interface management.
- Multiprogramming keeps multiple programs in memory.
- Multitasking allows multiple applications to appear to run together.
- Multiprocessing uses multiple CPUs or cores.
- A distributed OS manages multiple networked computers as one system.
- Windows is a GUI-based operating system developed by Microsoft.
- File Explorer manages Windows files and folders.
- Device Manager manages connected hardware and drivers.
- Linux is an open-source operating system inspired by UNIX.
- Popular Linux distributions include Ubuntu, Fedora, Debian and RHEL.
- Mobile operating systems include Android, iOS, HarmonyOS and KaiOS.
📝 Sample Board Exam Questions
Practice these questions while preparing Unit 3 for the NEB examination.
Group A: Multiple Choice Questions
- Microsoft Word
- Windows Operating System
- Adobe Photoshop
- Google Chrome
- Multitasking
- Multiprogramming
- Multiprocessing
- Time Sharing
- Windows
- macOS
- Linux
- iOS
Group B: Short Answer Question
Additional Practice Questions
- Differentiate between system software and application software with one example of each.
- Differentiate between multitasking and multiprocessing.
- Compare Windows and Linux in terms of source code, cost and common use.
- What is a mobile operating system? Give examples.
- What is open-source software?
- Explain the role of File Explorer in Windows.
Frequently Asked Questions
Software is a collection of instructions, programs or data that tells a computer what tasks to perform.
An operating system is system software that manages computer hardware and provides an interface between the computer and the user.
The main functions include process management, memory management, file management, device management, security and user-interface management.
Multitasking allows multiple programs to appear to run at the same time by rapidly switching CPU time, while multiprocessing uses multiple processors or CPU cores to execute tasks simultaneously.
An open-source operating system makes its source code available so users and developers can study, modify and distribute it according to its license.
Ubuntu, Fedora, Debian and Red Hat Enterprise Linux are common Linux distributions.
Conclusion
Unit 3 helps students understand how computer software and operating systems control and manage computer hardware.
For examination preparation, focus especially on software categories, operating system functions, multitasking, multiprocessing, Windows features, Linux and mobile operating systems.
Continue learning with Nepal eNotes for more NEB Class 11 Computer Science notes, solutions and exam preparation materials.
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