ICT-SKILLS Notes for Class 9

Ch-3 (ICT-SKILLS) 

 What is Computer System?

A Computer is an electronic machine that takes input from user, process the data and gives the desired result (output). It performs both mathematical and non-mathematical operations.

Computer can be classified into two categories.

1. Hardware: Any physically components that we can touch, feel,& view are called hardware. Ex- Monitor, Printer, Motherboard, RAM, SSD, Pen drive, Mouse,etc.

2. Software: A Software is a set of programs or instructions that tells the computer what to do. Ex: MS-Word, Excel, PowerPoint, Scratch, etc.

Software are two types:

System Software: It is a type of program that is designed and managed to all hardware devices'- Operating System(Windows, 7,10,11)

Application Software: It is a type of software designed to help users perform specific task. Ex: MS-Word, MS-Excel, Photoshop, CorelDRAW.

Hardware categories four types 

1. Input Device: Input devices are the devices that are used to enter data and instructions into a computer. Ex: Keyboard, Mouse, Scanner, Mike, Digital Camera, Joystick..

• Scanner: Scanner is an input device that is used to scan documents, photos, or images and coverts physical documents and images into digital format. Flatbed Scanner  and Handheld Scanner are the types of Scanners.
• Webcam: Webcam is an input device that captures video and images and sends them to the computer. Online classes, Video conferencing, Face recognition are uses of Webcam.
• Joystick: A Joystick is an input device used to control movement and direction in games and simulation programs.
• MICR : MICR stands for Magnetic Ink Character Recognition. It is a technology used to read cheque details with the help of magnetic ink and special machines. Uses of MICR in bank.

2. Process Device: Process device are the devices that process and execute data and instructions given by the user.

• CPU(Central Processing Unit): The CPU is the main components of a computer that processes data and controls all operations. ALU, CU and Registers are the parts of CPU. CPU is also known as brain of computer and is also known as Microprocessor.

1.  ALU(Arithmetic Logic Unit) : It performs all arithmetic operations like addition, subtraction , multiplication, division and logical operations like Greater than, Less than , equal to, etc. 
2. CU(Control Unit): The control unit is a part of the CPU that controls and manages all operations of a computer.
3. MU (Memory Unit) or Registers: Register is the smallest and fastest memory in a computer . It is not a part of main memory, it is located inside the CPU.

3. Output Device: The output device is a part of computer that displays or produces the processed results to the user.

• Monitor: Monitor is an output device that displays results in soft copy. It is also known as VDU (Visual Display Unit). 
• There are three types of Monitor. 
• CRT(Cathode Ray Tube) 
• LCD(Liquid Crystal Display)
• LED(Light Emitting Diode)

(II). Printer : Printers is an output device that is used to print text or images on paper. It converts soft copy to hard copy.

There are two types of Printers

• Impact Printers : Impact printers print by Shrinking an ink ribbon against paper. Ex: Dot Matrix Printer. Uses: Offices, Railway
• Non-impact Printers: Non-impact Printers print without striking the paper. They give better print quality. Ex: Inkjet, Laser Printers

(III). Projectors: Projector is an output device that projects and image onto a large surface, such as white screen, wall.

(IV). Plotters: Plotter is an output device that is used to print large-size drawings and graphics like maps, charts , engineering design and architecture.

4. Storage Unit: A storage unit is a part of computer that stores data, information, and instructions either temporarily or permanently.

Example: Hard-disk, Pen drive, RAM, ROM, etc.

There are two types of storage Unit.

1. Primary Storage: Primary Memory is the main memory of a computer that stores data and instructions temporarily or permanently for processing. It is directly accessed by the CPU.

                           There are two types of Primary Memory:

1. RAM(Random Access Memory): RAM is a volatile memory (data is deleted when power is off) that stores running programs and data temporarily for fast processing.

Dynamic RAM(DRAM) and Static RAM(SRAM) are the two types of RAM.

2. ROM(Read Only Memory): ROM is a Non-volatile memory that stores startup instructions and system programs required to boot the computer. 

Types of ROM:

• PROM(Programmable Read Only Memory)
• EPROM(Erasable Programmable Read only Memory)
• EEPROM(Electrical Erasable Programmable Read only Memory)

Secondary Unit : Secondary storage is a type storage device that stores data and information permanently for future use.

ex: Optical Disk Drives, USB drive, Hard disk, SSD, etc.

Optical Disk: An optical disk is a storage device that uses laser technology to store and read data.

Example: CD(Compact disc)- Storage capacity (700 MB), DVD -Storage capacity (4.7 GB), Blu-ray Disc- High storage capacity(25 GB)

Pen drive or USB: Pen Drive is a small portable storage device used to store and transfer digital data using a USB port.

Hard Disk : A hard disk is a permanent storage device used to store data, program, operating systems in a computer. Hard disk has large storage capacity (500 GB, 1 TB. 2 TB)

Peripherals devices: Peripheral devices are external devices connected to a computer to provide input, output, and storage functions.

Operating System: An operating system is a system software that acts as an interface between the user and hardware. It manages all hardware and software resources and allows  user to run program easily.  An operating system provides two types of interface.

• CUI/ CLI (Command User/ Line  Interface)
• GUI (graphical User Interface)

Functions of Operating system:

1. Process Management: Runs and manages programs.

2. Memory Management: Controls and allocates RAM.

3. File System Management: Manages files and folders 

4. Device Management: controls input and output devices.

5. Security: protects data and user accounts.

Types of Operating System:

1. Single user OS: A single user operating system is an OS that supports only one user at a time.

Ex: MS DOS, Windows 95

2. Multi-user OS: A multiuser operating system that allows multiple users to use a  computer system at the same time.

Example: Windows 7, Windows 10/11, Linux, Unix

3. Network Operating System: A network Operating system is an OS that manages network resources and allows computers to communicate and share data.

Ex: Windows Server 

4. Mobile OS:  A mobile operating system is an OS designed for mobile devices like smartphones, Tablet,etc. 

GUI based Interface: GUI is a type of interface that allows users to interact with a computer using graphics instead of typing commands.

Parts of GUI

1. Icon: A small pictures represents, a file , folder or program.

2. Menu: A list of commands .

3. Window: A rectangular area on the screen where a program runs.

4. Pointer(cursor): A small arrow used to select items on the screen.

Windows 7 Operating System: Windows 7 is a GUI-based operating system developed by Microsoft. It was released in 2009 and is used to run computers and manage hardware and software.

Components of Windows GUI:

1. Desktop: The main screen that appears after starting windows.

2. Start Button : Used to open the start menu and access programs

3. Start Menu: Contains list of programs and options like shut down.

4. Taskbar: The bar at the bottom of the screen that shows running programs.

File: A file is a collection of related information or data stored on a computer with a unique name and extension(.DOCX,.PPTX, .TXT)

Folders (Directory) ; A folder is a virtual container on a computer used to store and organize files.

Creating File and folder: 

Right click - New- File/Folder- Name- Enter

Windows Accessories:

1. Calculator: To perform arithmetic and scientific calculations.

2. MS-Paint: MS-Paint is a simple graphics programs in windows used to draw, color, and edit pictures.

3. WordPad: WordPad is a windows program used for writing and formatting text documents.

4. Snipping Tool: To take screenshots.

Common Desktop icons:

1. This PC/My Computer/Computer: Shows drives and system storage.

2. Recycle Bin: Recycle Bin is a desktop folder that temporarily stores deleted files for recovery or permanent deletion.

3. My network: My Network shows the computers and devices that are connected to the same network.

4. My Document: My documents is used to store personal files and documents. 

Internet: The Internet is a global network that connects millions of computers and devices around the world to share information and communication.

Internet Terminology:

1. WWW: WWW is a collection of web pages and websites connected through the internet.

2. Website: A website is a collection of webpages that are linked together.

3. Webpage: A webpage is a single document or page on the internet.

4. Web Browser: A web browser is a program that helps users access and view information on the WWW. Ex: Google Chrome, Opera Mini, Edge,etc.

5. Protocol: A protocol is a set of rules that control communication between devices in a network.

Ex: HTTPS, SMTP, FTP.

6. URL: A URL is the web address used to located and access resources on the internet.

Ex: https://www.google.com

7. HTTPS: HTTPS is a secure protocol used to transfer data safely over the internet.

E-MAIL: E-mail is a method of sending and receiving messages and files through the internet using an electronic device,

student@gmail.com ,abc123@yahoo.com, are the example of E-mail.

 Advantages of E-mail over traditional Mail:

1. Fast Delivery: Email is delivered instantly. while traditional mail takes time.

2. Low Cost: Email is cheaper because it uses the internet. 

3. File Attachment: Documents, images and videos can be sent easily.

Structure of an Email Address: An email address has three main parts.

1. User name: The name of the person or account. Ex- student in student@gmail.com

2. @ Symbol: Separates the username from the domain name. Ex- @in student@gmail.com

3. Domain Name: The mail server or provider.

Ex- gmail.com in student@gmail.com

Components of Gmail Window:

1. Inbox: It is a folder that stores all incoming emails.

2. Compose Mail: Compose mail is the option used to write and send a new email.

Parts of Composing mail

To: Receiver's email address.

Cc:  carbon copy(others can see)

Bcc: Blind carbon copy(other can't see)

Subject: Title of the email

Message: write your message 

3. Reply Mail: Reply mail is used to send a response to the sender of an email.

4. Sent : Sent is the folder where all emails you have sent are stored.

Cyber crime: cyber crime illegal activities done using computers ,mobile phones, and the internet to harm people, steal, money, or odd identity.

Cyber bullying: Cyberbullying is bullying that takes place through digital platforms to 

harm or disturb someone.

Example: 

Sending threatening messages on WhatsApp 

Posting embarrassing photos on social media.

Social Media: Social Media are digital platforms and websites that allows people to create, share , and exchange information , ideas, photos , and videos with others through the internet.

Ex: Facebook, Blog, LinkedIn, YouTube, Snap Chat, etc .

Blog:  The word "blog" comes from weblog . A blog is a type of website or online platform where a person ( called a blogger) regularly shares articles , opinion,  information , or experiences on different topics.

Personal Blog, Educational blog , Business Blog, are the types of Blog.                                         Popular blogging platform: Word press, Blogger, Medium, etc.

2. LinkedIn: LinkedIn is a professional networking website used to build career connections ,search for jobs , and share professional achievements.

3. YouTube: YouTube is an online video-sharing platform where users can upload , watch ,like, comments on , and share videos. It is widely used for entertainment , education , tutorials , news ,and live streaming.

Digital India: Digital India is a government initiative launched in 2015 by the Government of India to transform the country into a digitally empowered society and knowledge country.

Main objectives of Digital India:

1. Provide digital infrastructure as a core utility to every citizen.

2. Promote digital literacy and Encourage digital payments and e-governance .

Digi Locker: Digi Locker is an online platform that allows citizens to store and access official documents digitally. It ensures secure, paperless, and easy document management.

Answer the following questions answer:

1. What is tweeting and re-tweeting? What do you mean by #savetreescampaign?

Ans: Tweeting means posting a short message on Twitter (now called X).

Re-tweeting means sharing someone else's tweet with your followers.

#SaveTreesCampaign is a social media awareness campaign that encourages people to save and protect trees.

2. How operating systems performs data and storage management? 

Ans: An operating system manages data and storage by organizing files, allocating disk spaces, controlling memory, and protecting data from unauthorized access.