Information Technology माहिती तंत्रज्ञान

Quick summary

This chapter lays the foundation of IT. It explains IT and ICT, data and information, the parts and working of a computer, memory units, hardware and software, operating systems (including GNU/Linux and mobile OS), computer networks and the Internet, IT-enabled services, careers and recent trends.

Key points

• IT (Information Technology) is the use of computers to store, process and share information; ICT adds communication technologies like the Internet and mobile phones.
• Data are raw facts (numbers, words); information is processed data that is meaningful and useful.
• "Computer" comes from the Latin word computare, meaning to calculate.
• Block diagram: Input unit → CPU (ALU + Control Unit + memory) → Output unit. ALU does arithmetic and logic; CU coordinates all parts.
• Primary memory: RAM (read/write, volatile, temporary) and ROM (read only, permanent). Secondary storage: hard disk, pen drive, CD/DVD.
• Memory units: 1 bit (0 or 1); 4 bits = 1 nibble; 8 bits = 1 byte; 1 KB = 1024 bytes; 1 MB = 1024 KB; 1 GB = 1024 MB; 1 TB = 1024 GB.
• Hardware is the physical parts; software is the set of programs. Software types: system software (OS, utilities) and application software.
• Open-source software shares its source code freely (e.g. GNU/Linux, LibreOffice); proprietary software is owned and licensed (e.g. Windows).
• Desktop OS: Windows, GNU/Linux, macOS. Mobile OS: Android (free, open source), iOS and others.
• A network connects computers to share data and resources. Types by area: LAN, MAN, WAN. Architectures: client–server and peer-to-peer.
• The Internet began with ARPANET (funded by the US Department of Defense). TCP/IP was developed by Robert Kahn and Vinton Cerf in the 1970s.
• Protocols: HTTP (web pages), FTP (file transfer), SMTP (sending mail), POP/IMAP (receiving mail), DHCP (assigns IP addresses automatically).
• IT Enabled Services (ITES) give services through IT, like call centres, BPO, medical transcription and online support.
• Recent trends: AI, cloud computing, IoT, big data, blockchain, robotics, 3D printing.

Important terms

• Volatile memory – loses data when power is off (RAM).
• Operating system – software that manages hardware and lets users run programs.
• Protocol – set of rules for communication on a network.
• ITES – services delivered using IT and the Internet.

Formulas

5 important questions

Q1. Differentiate between data and information.

Data are raw, unorganised facts; information is data processed into a meaningful form that helps decisions.

Q2. What is the difference between RAM and ROM?

RAM is read/write and volatile (data lost when power goes); ROM is read-only and keeps its contents permanently.

Q3. Explain the types of networks based on area.

LAN covers a room, building or campus; MAN covers a city; WAN covers countries or the world (the Internet is the largest WAN).

Q4. Explain any four Internet protocols.

HTTP transfers web pages; FTP transfers files; SMTP sends e-mail; IMAP/POP receives e-mail; DHCP assigns IP addresses automatically.

Q5. What is open-source software? Give examples.

Software whose source code is freely available to use, change and share, e.g. GNU/Linux, LibreOffice, GIMP.

Exam tip

Memory unit conversions and expansions (RAM, ROM, LAN, HTTP, FTP) are frequent one-mark questions; learn them exactly.

Quick summary

This chapter introduces databases. It explains data vs information, what a database and a DBMS are, where DBMS is used and its advantages, data types, data models (mainly the relational model), keys and relationships, and the basics of SQL with its command categories.

Key points

• A database is a collection of interrelated data organised for easy storing, retrieving, inserting and deleting.
• A DBMS (Database Management System) is software to create and manage databases. Examples: MySQL, PostgreSQL, MS Access, Oracle, SQL Server, IBM DB2, Sybase, LibreOffice Base.
• Applications: railway reservation, library management, banking, schools/colleges, social media sites, hospitals.
• Advantages: less data redundancy (repetition), data consistency, easy sharing, data security (only authorised users), backup and recovery, integrity through rules.
• Common data types: CHAR (fixed-length text), VARCHAR (variable-length text), INT/INTEGER, DECIMAL/NUMERIC, DATE, TIME, BOOLEAN.
• A data model is the logical structure of a database. The relational model, the most popular, stores data in tables (relations).
• In a table, rows are records/tuples and columns are fields/attributes.
• Primary key: column(s) that uniquely identify each row. Foreign key: field in one table that refers to the primary key of another table.
• Relationships: one-to-one (person–passport), one-to-many (customer–orders), many-to-many (students–courses).
• SQL (Structured Query Language) is the standard language to work with relational databases.
• DDL defines structure: CREATE, ALTER, DROP, TRUNCATE. DML manages data: SELECT, INSERT, UPDATE, DELETE. DCL controls access: GRANT, REVOKE.

Important terms

• Redundancy – the same data stored again and again.
• RDBMS – DBMS based on the relational (table) model.
• Tuple – a row of a table.
• Attribute – a column of a table.
• SQL – Structured Query Language.

Formulas

Example: CREATE TABLE student (rollno INT PRIMARY KEY, name VARCHAR(30)); then SELECT * FROM student;

5 important questions

Q1. Define database and DBMS.

A database is a collection of related data stored in an organised way. A DBMS is software used to create, store, update and retrieve that data, e.g. PostgreSQL.

Q2. What is a primary key?

One or more columns that uniquely identify each row in a table, e.g. Roll No. It cannot repeat or be empty.

Q3. State any four advantages of DBMS.

Reduces redundancy, keeps data consistent, provides security to authorised users only, allows sharing among many users, and supports backup and recovery.

Q4. Explain the categories of SQL commands.

DDL (CREATE, ALTER, DROP) defines the database structure; DML (SELECT, INSERT, UPDATE, DELETE) handles the data; DCL (GRANT, REVOKE) controls user permissions.

Q5. Explain relationships in a database with examples.

One-to-one: one person has one passport. One-to-many: one customer places many orders. Many-to-many: many students join many courses, linked through a third table.

Exam tip

Remember which commands belong to DDL, DML and DCL; match-the-pair questions on them are common.

Quick summary

This chapter teaches how the web works and how to build web pages. The first part covers HTML5: page structure, text formatting, headings, images, tables, hyperlinks and forms. The second part introduces JavaScript, the scripting language that makes pages interactive: variables, data types, operators, built-in functions, decision statements, functions and events.

Key points

• The web works on a client–server model: the browser (client) requests a page using a URL, and the web server sends it back over HTTP.
• Components of the web: web page, website, web browser (Chrome, Firefox), web server, URL, ISP.
• HTML (HyperText Markup Language) uses tags in angle brackets; most come in pairs like <b>…</b>. HTML5 is the current version.
• Basic structure: <!DOCTYPE html>, <html>, <head> (with <title>), <body>.
• Formatting tags: <b>, <i>, <u>, <sup>, <sub>, <p>, <br>; headings <h1> (largest) to <h6> (smallest).
• <img src="…" alt="…"> inserts an image; <hr> draws a horizontal line.
• Tables use <table>, <tr> (row), <th> (header cell), <td> (data cell); attributes border, colspan, rowspan.
• Hyperlinks use <a href="URL">; links can go to another page, site, or part of the same page.
• Forms collect input with <form> and controls: text, password, radio, checkbox, submit, reset, <select> and <textarea>.
• JavaScript runs in the browser and is written inside <script>. It is case sensitive.
• Variables are declared with var (or let); data types include number, string, boolean, null and undefined.
• Operators: arithmetic (+ − * / %), assignment (=, +=), relational (==, !=, <, >), logical (&&, ||, !), increment ++ and decrement −−.
• Built-in functions: alert(), prompt(), confirm(), parseInt(), parseFloat(), isNaN(), document.write().
• Decision making: if, if…else, else if ladder. User-defined functions are made with the keyword function and can be called on events like onclick.

Important terms

• URL – address of a resource on the web.
• Tag – HTML instruction written in angle brackets.
• Attribute – extra information inside a tag, like src or href.
• Script – small program run by the browser.
• Event – action such as a click that can start a function.

Formulas

5 important questions

Q1. Explain the basic structure of an HTML5 document.

It starts with the doctype declaration, then the html element containing head (title and meta information) and body (the visible content).

Q2. What is the difference between <th> and <td>?

<th> creates a header cell, shown bold and centred; <td> creates a normal data cell.

Q3. List the form controls in HTML with their use.

Text box (single line text), password (hidden characters), radio button (choose one), checkbox (choose many), select (drop-down list), textarea (multi-line text), submit and reset buttons.

Q4. Explain any four JavaScript operators with examples.

Arithmetic: a + b; assignment: x += 5; relational: a > b gives true or false; logical: (a > 0 && b > 0) is true only if both are true.

Q5. Write a JavaScript program to check whether a number is even or odd.

var n = parseInt(prompt("Enter number")); if (n % 2 == 0) alert("Even"); else alert("Odd");

Exam tip

Write tags exactly with angle brackets and closing slashes. Practise one table with colspan/rowspan and one form; they are common practical questions.

Quick summary

Cyber law deals with crimes and legal issues linked to computers and the Internet. This chapter covers ethics and morals in using technology, types of cyber crime, cyber safety and security measures, and the Information Technology Act, 2000 of India, with case studies on phishing and fraud.

Key points

• Cyber law covers freedom of expression, access to and use of the Internet, and online privacy. It gives legal ways to deal with cyber crimes.
• Ethics are rules of right and wrong; using technology ethically includes respecting others online and following netiquette (Internet etiquette).
• Cyber crime (e-crime, hi-tech crime) is crime using computers or networks: hacking, theft, fraud, forgery, defamation.
• Examples: phishing (fake e-mails/sites to steal card numbers, passwords), hacking bank accounts, stealing organisational data, software piracy (copying software illegally), copyright violation and plagiarism (presenting others' work as yours), cyber bullying, identity theft, spreading viruses.
• Never share OTP, card number, CVV, expiry date, ATM PIN, net-banking ID or password with anyone, even a caller claiming to be from the bank.
• Safety measures: strong passwords changed regularly, do not save passwords in browsers, antivirus software, firewall (hardware/software that blocks unwanted traffic), updates, logging out, avoiding unknown links.
• Students' do's and don'ts: don't steal others' information, don't access files without permission, don't use pirated software, report cyber bullying.
• The IT Bill was passed by Parliament in May 2000 and got the President's assent in August 2000, becoming the Information Technology Act, 2000.
• The IT Act gives legal recognition to electronic records and transactions (EDI, e-commerce) and digital signatures, and defines punishments for cyber crimes.
• It defines a cyber café, sets up a Cyber Regulations Advisory Committee and lays down the justice system for cyber crimes.
• The Act was amended in 2008 and 2011 (rules for cyber cafés, cyber security, service delivery, audit of electronic documents).

Important terms

• Cyber crime – illegal activity done using a computer or the Internet.
• Phishing – tricking people into giving confidential details through fake messages or sites.
• Software piracy – illegal copying or distribution of software.
• Plagiarism – copying someone's work and presenting it as one's own.
• Firewall – security system that blocks unauthorised network traffic.

Formulas

5 important questions

Q1. What is cyber law?

The law dealing with legal issues of computers, the Internet and electronic communication, including cyber crimes, privacy and e-commerce.

Q2. What is phishing?

A cyber crime in which fake e-mails, calls or websites pretending to be a bank or company trick users into revealing passwords, card numbers or OTPs.

Q3. Explain any four types of cyber crime.

Hacking (unauthorised access to systems or accounts), software piracy (illegal copying), phishing (stealing confidential data by deceit), cyber bullying (harassing someone online), identity theft.

Q4. State the salient features of the IT Act, 2000.

Legal recognition of electronic records and digital signatures, legal framework for e-commerce, acceptance of contracts by electronic means, definition of cyber café, Cyber Regulations Advisory Committee, punishment and justice system for cyber crimes.

Q5. What precautions should we take to stay safe online?

Use strong passwords and never share OTP/PIN, install antivirus and firewall, avoid suspicious links and attachments, keep software updated, log out after use.

Exam tip

Case-study questions ask you to name the crime (e.g. phishing) and suggest precautions; practise identifying the crime from a short story.