What are the key internet protocols and concepts?

Internet basics: Internet = global network of networks using TCP/IP protocols. World Wide Web (WWW): Information system on internet; Tim Berners-Lee invented (1989, CERN). Key protocols: TCP (Transmission Control Protocol) — ensures data delivery; IP (Internet Protocol) — addressing/routing; HTTP (HyperText Transfer Protocol) — web pages; HTTPS (S=Secure, encrypted); FTP (File Transfer Protocol) — file sharing; SMTP — email. IP Address: Unique number identifying device on network; IPv4 (32-bit, 4.3 billion addresses — exhausting); IPv6 (128-bit, virtually unlimited). DNS (Domain Name System): Translates domain names (google.com) to IP addresses — 'phone book of internet'. URL: Uniform Resource Locator — complete web address. Bandwidth: Data transfer rate; measured in Mbps/Gbps. 5G: 5th generation mobile network; speeds up to 20 Gbps; latency <1ms; enables IoT, autonomous vehicles, smart cities. India's 5G: Launched October 2022 by PM Modi; Jio and Airtel deployed; India among fastest 5G rollouts. Satellite internet: Starlink (SpaceX), OneWeb, ISRO GSAT — connecting rural/remote areas.

What is Artificial Intelligence and how is it being used in India?

Artificial Intelligence (AI): Computer systems that perform tasks typically requiring human intelligence — learning, reasoning, problem-solving, speech recognition, visual perception. Key concepts: Machine Learning (ML): Algorithms that learn from data; types — supervised, unsupervised, reinforcement learning. Deep Learning: ML using neural networks (layers of algorithms inspired by human brain). Natural Language Processing (NLP): Computers understand human language — ChatGPT, Google Translate. Computer Vision: Image recognition — facial recognition, medical imaging, autonomous vehicles. AI in India: (1) National AI Strategy 2021 — India as 'AI for All' country; NITI Aayog framework. (2) IndiaAI Mission (2024): ₹10,300 crore investment; 10,000 GPUs compute cloud; AI startups; responsible AI. (3) Applications: DigiLocker (AI-powered document storage), Aarogya Setu (contact tracing), crop monitoring by drones, traffic management. (4) Tamil Nadu AI: TN leads in AI adoption — Ola, Freshworks, Zoho headquartered in Chennai; Tamil NLP projects. Generative AI: ChatGPT (OpenAI), Gemini (Google), Claude (Anthropic) — transform content creation, coding, analysis. India regulation: Digital Personal Data Protection Act 2023 — data privacy; AI regulation framework under development.

What is cybersecurity and what are the major cyber threats?

Cybersecurity: Protection of computers, networks, data from digital attacks, damage, or unauthorised access. Major cyber threats: (1) Malware: Malicious software — Virus (attaches to files, spreads), Worm (self-replicates via network), Trojan (disguised as legitimate software), Ransomware (encrypts files, demands payment), Spyware (monitors user activity). (2) Phishing: Fraudulent emails/messages impersonating trusted sources to steal credentials or money. (3) DDoS (Distributed Denial of Service): Overwhelming server with traffic to make it unavailable. (4) Man-in-the-Middle: Intercepting communication between two parties. (5) Zero-day exploits: Attacks on unknown vulnerabilities before patch released. India's cybersecurity framework: CERT-In (Computer Emergency Response Team-India): National agency for cybersecurity incident response under MeitY. IT Act 2000 (amended 2008): Covers cybercrime; Section 66 (hacking), 66A (struck down — free speech), 66C (identity theft), 66D (cheating by personation), 67 (obscene material). NCSP (National Cyber Security Policy 2013): Framework for protecting cyberspace. Digital Personal Data Protection Act 2023: India's first comprehensive data protection law — rights of data principal; duties of data fiduciary.

What is blockchain technology and what are its applications?

Blockchain: Distributed, decentralised digital ledger that records transactions across many computers — no central authority; once recorded, data cannot be altered. Key features: (1) Decentralised: No single point of control; nodes hold copies. (2) Immutable: Each block linked to previous via cryptographic hash; altering one block invalidates all subsequent. (3) Transparent: All participants can view transactions (in public blockchains). (4) Consensus: Majority of nodes must agree on new blocks (Proof of Work, Proof of Stake). Bitcoin: First major blockchain application (2008, Satoshi Nakamoto); digital currency (cryptocurrency). Ethereum: Blockchain supporting smart contracts — self-executing contracts with terms in code. Applications beyond cryptocurrency: (1) Supply chain: Track goods from farm to shelf; prevent counterfeiting. (2) Healthcare: Secure medical records. (3) Land records: Andhra Pradesh and Telangana piloted blockchain land registrations. (4) Voting: Tamper-proof digital voting (experimental). (5) Digital identity: Aadhaar-linked blockchain for identity verification. India and crypto: India's stance ambiguous — 30% tax on crypto gains + 1% TDS (Budget 2022); no blanket ban; RBI cautious. CBDC (Central Bank Digital Currency): RBI launched Digital Rupee (e₹) pilot 2022 — government-issued digital currency on blockchain.

Computer Science & Information Technology — TNPSC Group 1 Notes

Q: What are the basic components of a computer and how does it process data?

Computer components: (1) CPU (Central Processing Unit): Brain of computer; performs arithmetic and logical operations; measured in GHz (clock speed) and cores (parallel processors). (2) RAM (Random Access Memory): Temporary working memory; data lost when power off; measured in GB. (3) ROM (Read-Only Memory): Permanent memory; stores BIOS/firmware; not erased when powered off. (4) Storage: HDD (Hard Disk Drive — magnetic, slower, cheaper), SSD (Solid State Drive — flash memory, faster, expensive). (5) Input devices: Keyboard, mouse, scanner, webcam. (6) Output devices: Monitor, printer, speakers. (7) Motherboard: Main circuit board connecting all components. Data units: 1 Byte = 8 bits; 1 KB = 1,024 bytes; 1 MB = 1,024 KB; 1 GB = 1,024 MB; 1 TB = 1,024 GB; 1 PB = 1,024 TB. Number systems: Binary (base-2, used by computers), Decimal (base-10), Hexadecimal (base-16). Generations of computers: 1st (vacuum tubes, 1940s), 2nd (transistors, 1950s), 3rd (integrated circuits, 1960s), 4th (microprocessors, 1970s-present), 5th (AI-based, developing).

Q: What is Artificial Intelligence and how is it being used in India?

Artificial Intelligence (AI): Computer systems that perform tasks typically requiring human intelligence — learning, reasoning, problem-solving, speech recognition, visual perception. Key concepts: Machine Learning (ML): Algorithms that learn from data; types — supervised, unsupervised, reinforcement learning. Deep Learning: ML using neural networks (layers of algorithms inspired by human brain). Natural Language Processing (NLP): Computers understand human language — ChatGPT, Google Translate. Computer Vision: Image recognition — facial recognition, medical imaging, autonomous vehicles. AI in India: (1) National AI Strategy 2021 — India as 'AI for All' country; NITI Aayog framework. (2) IndiaAI Mission (2024): ₹10,300 crore investment; 10,000 GPUs compute cloud; AI startups; responsible AI. (3) Applications: DigiLocker (AI-powered document storage), Aarogya Setu (contact tracing), crop monitoring by drones, traffic management. (4) Tamil Nadu AI: TN leads in AI adoption — Ola, Freshworks, Zoho headquartered in Chennai; Tamil NLP projects. Generative AI: ChatGPT (OpenAI), Gemini (Google), Claude (Anthropic) — transform content creation, coding, analysis. India regulation: Digital Personal Data Protection Act 2023 — data privacy; AI regulation framework under development.

Q: What is cybersecurity and what are the major cyber threats?

Cybersecurity: Protection of computers, networks, data from digital attacks, damage, or unauthorised access. Major cyber threats: (1) Malware: Malicious software — Virus (attaches to files, spreads), Worm (self-replicates via network), Trojan (disguised as legitimate software), Ransomware (encrypts files, demands payment), Spyware (monitors user activity). (2) Phishing: Fraudulent emails/messages impersonating trusted sources to steal credentials or money. (3) DDoS (Distributed Denial of Service): Overwhelming server with traffic to make it unavailable. (4) Man-in-the-Middle: Intercepting communication between two parties. (5) Zero-day exploits: Attacks on unknown vulnerabilities before patch released. India's cybersecurity framework: CERT-In (Computer Emergency Response Team-India): National agency for cybersecurity incident response under MeitY. IT Act 2000 (amended 2008): Covers cybercrime; Section 66 (hacking), 66A (struck down — free speech), 66C (identity theft), 66D (cheating by personation), 67 (obscene material). NCSP (National Cyber Security Policy 2013): Framework for protecting cyberspace. Digital Personal Data Protection Act 2023: India's first comprehensive data protection law — rights of data principal; duties of data fiduciary.

Q: What is blockchain technology and what are its applications?

Blockchain: Distributed, decentralised digital ledger that records transactions across many computers — no central authority; once recorded, data cannot be altered. Key features: (1) Decentralised: No single point of control; nodes hold copies. (2) Immutable: Each block linked to previous via cryptographic hash; altering one block invalidates all subsequent. (3) Transparent: All participants can view transactions (in public blockchains). (4) Consensus: Majority of nodes must agree on new blocks (Proof of Work, Proof of Stake). Bitcoin: First major blockchain application (2008, Satoshi Nakamoto); digital currency (cryptocurrency). Ethereum: Blockchain supporting smart contracts — self-executing contracts with terms in code. Applications beyond cryptocurrency: (1) Supply chain: Track goods from farm to shelf; prevent counterfeiting. (2) Healthcare: Secure medical records. (3) Land records: Andhra Pradesh and Telangana piloted blockchain land registrations. (4) Voting: Tamper-proof digital voting (experimental). (5) Digital identity: Aadhaar-linked blockchain for identity verification. India and crypto: India's stance ambiguous — 30% tax on crypto gains + 1% TDS (Budget 2022); no blanket ban; RBI cautious. CBDC (Central Bank Digital Currency): RBI launched Digital Rupee (e₹) pilot 2022 — government-issued digital currency on blockchain.

Computer Hardware Basics

Computer Components

Processing:

CPU (Central Processing Unit): Executes instructions; speed in GHz (gigahertz); modern CPUs have 4–64+ cores
GPU (Graphics Processing Unit): Specialised for graphics + parallel computing; essential for AI/ML training

Memory:

RAM (Random Access Memory): Fast temporary storage; data lost on power off; 8–128 GB typical in modern computers
ROM (Read-Only Memory): Permanent; stores boot firmware (BIOS/UEFI); not erased
Cache: Ultra-fast memory inside CPU (L1/L2/L3)

Storage:

HDD (Hard Disk Drive): Magnetic spinning disks; slow; cheap; 1–10 TB
SSD (Solid State Drive): Flash memory; fast; no moving parts; 256 GB–8 TB
Cloud Storage: Remote servers (Google Drive, OneDrive, iCloud)

Data Units:

Unit	Size
1 Bit	0 or 1
1 Byte	8 bits
1 Kilobyte (KB)	1,024 bytes
1 Megabyte (MB)	1,024 KB
1 Gigabyte (GB)	1,024 MB
1 Terabyte (TB)	1,024 GB
1 Petabyte (PB)	1,024 TB

Generations of Computers:

Generation	Technology	Era
1st	Vacuum tubes	1946–1955 (ENIAC, UNIVAC)
2nd	Transistors	1956–1963
3rd	Integrated circuits (ICs)	1964–1971
4th	Microprocessors	1972–present
5th	AI, quantum computing	Emerging

Internet and Networking

How Internet Works

Internet: Global network of networks using TCP/IP
WWW (World Wide Web): Information system accessible via internet; invented by Tim Berners-Lee (1989, CERN, Geneva)

Key Protocols:

Protocol	Full form	Use
TCP/IP	Transmission Control/Internet Protocol	Core internet; data delivery + addressing
HTTP	HyperText Transfer Protocol	Web pages
HTTPS	HTTP Secure (SSL/TLS encrypted)	Secure web (banking, shopping)
FTP	File Transfer Protocol	File sharing
SMTP/POP3	Email protocols	Send/receive email
DNS	Domain Name System	Translates domain names to IP addresses

IP Address:

IPv4: 32-bit (e.g., 192.168.1.1) — ~4.3 billion addresses (nearly exhausted)
IPv6: 128-bit — virtually unlimited addresses; being deployed

Mobile Networks

Generation	Speed	Key Feature
2G	10-30 kbps	SMS, voice calls
3G	2-7 Mbps	Mobile internet, video calls
4G/LTE	20-100 Mbps	HD video, apps
5G	1-20 Gbps	Ultra-low latency (<1ms); IoT; smart cities

India 5G: Launched October 1, 2022 (PM Modi); Jio and Airtel; among world's fastest rollouts in terms of coverage; Tamil Nadu — all major cities covered

Artificial Intelligence

Key Concepts

Term	Definition
AI	Computer systems performing human-intelligence tasks
Machine Learning	Algorithms learning patterns from data
Deep Learning	Multi-layer neural networks; image/speech recognition
NLP	Natural Language Processing; computers understand text/speech
Computer Vision	Machines interpret visual information
Generative AI	AI that creates new content (text, images, music)

AI Applications in India

Government:

DigiLocker: Aadhaar-linked digital document storage
UMANG App: Unified Mobile Application for New-age Governance — 1,200+ govt services
Aarogya Setu: COVID-19 contact tracing; used Bluetooth + GPS + AI

Agriculture:

Crop disease detection via satellite/drone images
Soil health monitoring
Price prediction for agricultural markets

Healthcare:

AI radiology tools (X-ray, CT scan interpretation)
Drug discovery acceleration
Telemedicine + AI diagnosis for rural areas

Finance:

UPI fraud detection (real-time AI)
Credit scoring for new-to-credit borrowers
Mutual fund robo-advisors

India's AI Policy

NITI Aayog AI Strategy: "AI for All" — focus on agriculture, health, education, smart mobility, smart cities

IndiaAI Mission (2024):

₹10,300 crore (2024-2029)
Build shared compute infrastructure (10,000 GPUs accessible to researchers/startups)
AI innovation centres
Responsible AI governance framework

Tamil Nadu IT: Chennai = India's 2nd largest IT hub; Tidel Park, OMR corridor; major companies: TCS, Infosys, Wipro, Cognizant, HCL; homegrown: Zoho, Freshworks; AI startups growing

Cybersecurity

Types of Cyber Threats

Threat	Description
Virus	Self-replicating code that attaches to files and spreads
Worm	Self-replicating via networks; no host file needed
Trojan Horse	Disguised as legitimate software; opens backdoor
Ransomware	Encrypts data; demands payment (WannaCry 2017)
Phishing	Fake emails/messages to steal credentials
DDoS	Overwhelm server with traffic to disable it
Spyware	Silently monitors user activity; steals data
Social Engineering	Manipulating humans (not systems) to gain access

Major global cyber attacks:

WannaCry (2017): Ransomware affected 150+ countries; exploited Windows vulnerability
Colonial Pipeline (2021): US fuel pipeline shut for days via ransomware

India's Cybersecurity Framework

CERT-In (Computer Emergency Response Team — India):

National nodal agency for cybersecurity; under MeitY
Coordinates incident response; issues advisories

IT Act 2000 (Information Technology Act, amended 2008):

Section	Offence
43	Unauthorised access to computer
66	Computer-related offences (hacking)
66A	Struck down by SC (2015) — was criminalising online speech
66C	Identity theft
66D	Fraud/cheating using computer
67	Obscene material online
69	Government power to intercept/monitor

Digital Personal Data Protection Act 2023 (DPDP Act):

India's first comprehensive data protection law
Data Principal: Individual whose data is processed
Data Fiduciary: Entity that determines purpose/means of processing
Rights: Access, correction, erasure, grievance redressal
Consent required for data collection; specific purpose required
Data Localisation: Certain categories of sensitive data must be stored in India
Heavy penalties for violation (up to ₹250 crore)

Blockchain and Emerging Technologies

Blockchain

Structure: Chain of blocks; each block = set of transactions + hash of previous block + timestamp

Properties:

Immutable: Cannot alter past records
Decentralised: No single controlling authority
Transparent: Visible to all participants (public blockchain)
Secure: Cryptographic linking

Consensus Mechanisms:

Proof of Work (PoW): Mining — computational puzzle; energy-intensive (Bitcoin)
Proof of Stake (PoS): Validators stake coins — energy efficient (Ethereum 2.0)

Applications:

Application	Example
Cryptocurrency	Bitcoin, Ethereum
Smart contracts	Ethereum; self-executing agreements
Supply chain	IBM Food Trust; Walmart food tracking
Land records	AP, Telangana pilots
Healthcare	Secure patient data sharing

Digital Rupee (e₹)

RBI launched CBDC (Central Bank Digital Currency) pilot — December 2022

Wholesale pilot (banks): November 2022
Retail pilot (public): December 2022
Digital form of Indian rupee; legal tender
Not cryptocurrency — government-backed, centralised

Cloud Computing

Delivery models:

IaaS (Infrastructure as a Service): Rent computing infrastructure (AWS EC2)
PaaS (Platform as a Service): Development platform (Google App Engine)
SaaS (Software as a Service): Software over internet (Gmail, Office 365)

Deployment types: Public cloud (AWS, Azure, Google)	Private cloud	Hybrid

India cloud: National Cloud (MeghRaj) — government services hosted domestically; data sovereignty

Social Media and Digital Regulation

IT Rules 2021 (Information Technology — Intermediary Guidelines and Digital Media Ethics Code Rules)

For Social Media Intermediaries:

Significant Social Media Intermediaries (50 lakh+ users): Must appoint:
Chief Compliance Officer (CCO)
Nodal Contact Person
Resident Grievance Officer (all in India)
Monthly compliance reports to government
Must respond to government requests within 72 hours (cybersecurity emergencies)
Traceability: Must identify originator of WhatsApp-type end-to-end messages — controversial privacy debate

For Digital News Media:

Three-tier grievance mechanism: Self-regulation → Industry body → MIB oversight
Content prohibited if promotes terrorism, sovereignty threats, obscenity

IT Amendment Rules 2023:

Fact Check Unit of PIB can label government-related content as "fake" — SC stayed

Board Exam Tips

CPU: Central Processing Unit; 5th generation computers = AI-based
Data units: Bit → Byte (8 bits) → KB → MB → GB → TB → PB
WWW invented: Tim Berners-Lee (1989, CERN)
5G India: Launched October 1, 2022; speeds up to 20 Gbps
AI types: ML → Deep Learning → NLP → Computer Vision → Generative AI
IndiaAI Mission (2024): ₹10,300 crore; 10,000 GPUs
CERT-In: National cybersecurity agency; under MeitY
IT Act 2000: Section 66A struck down (2015); 66C = identity theft; 67 = obscene content
DPDP Act 2023: India's first data protection law; consent required; up to ₹250 crore penalty
Blockchain: Decentralised + Immutable + Transparent; Bitcoin = first major application
Digital Rupee (e₹): RBI CBDC; launched December 2022; not cryptocurrency
IT Rules 2021: Significant Social Media = 50 lakh+ users; must appoint CCO, grievance officer
Tamil Nadu IT: Chennai = 2nd largest IT hub; Zoho, Freshworks; OMR = IT corridor

Frequently Asked Questions

Computer components: (1) CPU (Central Processing Unit): Brain of computer; performs arithmetic and logical operations; measured in GHz (clock speed) and cores (parallel processors). (2) RAM (Random Access Memory): Temporary working memory; data lost when power off; measured in GB. (3) ROM (Read-Only Memory): Permanent memory; stores BIOS/firmware; not erased when powered off. (4) Storage: HDD (Hard Disk Drive — magnetic, slower, cheaper), SSD (Solid State Drive — flash memory, faster, expensive). (5) Input devices: Keyboard, mouse, scanner, webcam. (6) Output devices: Monitor, printer, speakers. (7) Motherboard: Main circuit board connecting all components. Data units: 1 Byte = 8 bits; 1 KB = 1,024 bytes; 1 MB = 1,024 KB; 1 GB = 1,024 MB; 1 TB = 1,024 GB; 1 PB = 1,024 TB. Number systems: Binary (base-2, used by computers), Decimal (base-10), Hexadecimal (base-16). Generations of computers: 1st (vacuum tubes, 1940s), 2nd (transistors, 1950s), 3rd (integrated circuits, 1960s), 4th (microprocessors, 1970s-present), 5th (AI-based, developing).