Class 11 IT (Information Technology) - 1.Basics Of information Technology (Short Notes)
1. What is Information Technology (IT)?
Information Technology, or IT, simply means using computers to handle information — to store it, find it, send it, or use it in different ways.
Almost everything we do using a computer, mobile phone, or the internet — like chatting, watching videos, or working on documents — is a part of IT.
2. Data vs. Information
Data: These are just raw facts or numbers without any meaning.
Example: 15, Suresh, Cricket
Information: When data is arranged or organized properly, it becomes meaningful.
Example: Suresh, who is 15 years old, likes to play cricket.
💡 Think of data as loose puzzle pieces, and information as the complete picture.
3. Parts of a Computer System
A computer mainly has two important parts:
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Hardware: The parts you can touch and see.
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Software: The set of programs that tell the hardware what to do.
4. Hardware (The Body)
Input Devices: These are used to give instructions or data to the computer.
Examples: Keyboard, Mouse, Scanner, Microphone
CPU (Central Processing Unit):
This is the brain of the computer. It processes all data and performs calculations.
Output Devices: These show the results after processing.
Examples: Monitor, Printer, Speakers
Storage (Memory): This is where data and information are stored.
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Primary Memory (RAM):
This is temporary memory — data disappears when the power is turned off. -
Secondary Memory (Hard Disk, Pen Drive, SSD):
This is permanent memory — data stays safe even after the power is off.
(It’s like a cupboard where you keep things for later use.)
5. Software (The Soul)
System Software (Operating System – OS):
This is the main software that manages all computer activities.
Without it, a computer can’t work.
Examples: Windows, Android, macOS
Application Software (Apps):
These are programs made for specific purposes.
Examples: Google Chrome (for browsing), MS Word (for typing), WhatsApp (for chatting), Games.
6. Units of Memory (How We Measure Data)
From smallest to largest unit:
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Bit: The smallest unit (0 or 1)
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Byte: 8 bits
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Kilobyte (KB): 1024 bytes → roughly the size of a small text file
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Megabyte (MB): 1024 KB → size of a song
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Gigabyte (GB): 1024 MB → size of a movie
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Terabyte (TB): 1024 GB → size of a large hard disk
7. Types of Computers
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Microcomputer: Used by one person for everyday tasks — Desktop, Laptop.
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Minicomputer: Used by small or medium companies — supports several users.
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Mainframe Computer: Very large and powerful — used by banks, railways, and big organizations.
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Supercomputer: The fastest and most powerful — used for scientific research and weather prediction.
8. Computer Networks (Connecting Computers)
When two or more computers are connected to share data and resources, it’s called a network.
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LAN (Local Area Network): Covers a small area like a home, school, or office.
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MAN (Metropolitan Area Network): Covers a city or large campus.
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WAN (Wide Area Network): Covers large distances — even countries.
🌐 The Internet is the biggest example of a WAN.
9. Computer Safety and Ethics
Virus/Malware: Harmful programs that can damage your computer or steal your data.
🛡️ Use antivirus software to keep your system safe.
Computer Ethics: The correct and moral way of using computers.
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Don’t misuse or steal others’ data.
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Don’t install or use pirated software.
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Keep your password secret and protect your personal information.
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