Computer Science (SLO Based) Notes 


Unit-1 

"Introduction to Computers"

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Brief/Long Response Questions and Answers:

Q2. What is Computer Software? Explain in Detail.

Ans: 

Computer Software:

Software is a set of instructions given to computers for performing tasks and solving problems. Also called programs. 

Examples: Word processors, spreadsheets, games, database management systems, etc.


Types of computer software:

Computer software can be classified into:


  1. System software
  2. Application software
  3. Internet applications
  4. Licensed software, open source software, shareware, and freeware.

    1. System software:

    Software that controls and coordinates the activities of a computer system is called system software. It consists of programs designed to control hardware and manage software.

    Types of system software:

    1. Operating system
    2. Device drivers
    3. Utility software
    4. Language processors/ translators


    1. Operating system:

    It controls and manages the hardware and software resources of the computer system and provides a user interface. A computer cannot work without an operating system.

    Examples: Windows, LINUX , UNIX, MAC OS, Android, IOS, etc.


    Tasks of the operating system:

    • Loading and execution of programs.
    • Allocating resources.
    • Memory management.
    • File management
    • Storage management
    • Providing user interface.
    • Maintain security.
    • Provide network facility.

    2. Device Drivers:

    • Software that controls the operation of hardware devices.
    • Any device attached to the computer will not work properly without device drivers.
    • Device drivers are provided by device manufacturers.
    • Plug and Play devices have their drivers preinstalled in Windows.

    3. Utility software:

    • Perform functions that are beyond the capability of the operating system.
    • Users can perform tasks easily and efficiently.

    Examples: File manager, disk management utility, disk defragmenter, antivirus, file compression software, etc.

    4. Language processors/ translators:

    • Computer can only understand machine language which is in the form of 0 and 1.
    • Programs are written in assembly language or high-level language.
    • Language processors convert programs written in assembly or high-level language into machine language.

    Types of Language Processors:

    There are three types of language processors

    Assembler: 

    It translates assembly language program into machine language.

    Compiler: 

    it converts a high-level language program into machine language. The entire program is converted into machine language using the compiler.

    Interpreter: 

    It also converts a high-level language program into machine language. It translates one instruction at a time goes to the next instruction after executing the previous one.

    2. Application software:

    Application software is used to perform a particular task. For example word processors, games, spreadsheet software etc. 

    Examples:

    1. Productivity software.
    2. Business software.
    3. Entertainment software.
    4. Educational software.

    1. Productivity software:

    • Designed to perform daily activities effectively and efficiently.
    • Word processors, spreadsheets, database management systems, and graphic software are a few examples.


    2. Business software: 

    • It helps in performing business activities efficiently.
    • For example payroll, inventory, accounting, etc.


    3. Entertainment software:

    • It is used to entertain people
    • Examples: games,, media players, music software, etc.

    4. Educational software:

    • Used for learning purposes
    • Examples: teaching about the human body, solar system, languages, typing, etc

    3. Internet Applications:
    1. Web applications
    2. Cloud computing applications
    3. Social media network application

    1. Web applications:

    • These programs run on a remote server.
    • Users can interact with it using a browser or a client application.
    • Examples: e-mail services, online banking, online ticket reservation, etc.

    2. Cloud computing applications:

    • It supports cloud computing.
    • Users can access data and applications stored on a remote server using this application
    Examples: iCloud, dropbox, etc.


    3. Social media network application:

    • Social media allows people to create and exchange information, ideas, interests, etc.
    • It connects users with their friends, families, or colleagues.

    Some popular Social media network applications are

    i) Facebook:

    • It is the most popular social media network application connecting billions of people around the world.
    • It allows users to create profiles, exchange messages, and share photos videos, and links.
    • Users can also create pages and groups based on common interests.

    ii) Twitter:

    • It is a news and social networking service
    • It allows users to broadcast short messages called tweets to other subscribers.
    • People can share their views about current affairs or other topics.

    iii) WhatsApp;

    • It is a free messaging service to exchange text, photos, audio or video, etc.
    • It is very popular among people due to the features like audio and video call group chat, location sharing, etc.
    • Available for all smartphone operating systems (iPhone, Android, Nokia, etc.)


    4,. Licensed software, open source software, shareware/trialware freeware    , and firmware.

    Licensed software:

    • A license is a legal agreement that gives the user the right to use the software.
    • Licensed software is protected by copyright laws.
    • One cannot make illegal copies of licensed software.
    • Software copied or sold without the permission of the owner is called pirated software.
    Example: Microsoft Windows, Microsoft Office, etc.


    Open source software:

    • A software whose source code is available for users to study, change or improve it.
    • It is free for inspection modification and distribution.
    Examples: LINUX, Open Office, etc.


    Shareware    /trialware:

    • It is available free for a limited time period called a trial period.
    • After the trial period expires user has to purchase the software.
    • The trial version may have limited features or it stops working after it expires.
    Examples: antivirus etc.

    Freeware:

    • It is available free with full features for unlimited time.
    • It may have some restrictions like personal or educational use.
    Examples: Browsers, SKYPE, games, Viber, etc


    Firmware:

    • The intermediate form between hardware and software
    • Software embedded in devices during manufacturing.
    • Programs stored in it do not need to be changed.
    • Data is not lost used power is off.
    Examples: toys, appliances, ROM, etc.

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    Unit-1 (Important Short Q/A)


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    (National Book Foundation - As Federal Textbook Board, Islamabad 
    Based on National Curriculum Pakistan 2026-2027 and Onward prescribed by Federal Board of Intermediate and Secondary Education, Islamabad, and All Pakistan Boards) 

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