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Key Points at a Glance
Computer Networks
- Interconnected computers sharing resources
- Types by geography: PAN (~10m), LAN (building/campus), MAN (city), WAN (global — Internet is the largest WAN)
- IP address: unique identifier for devices on network
- IPv4: 32-bit; ~4.3 billion addresses — exhausted
- IPv6: 128-bit; virtually unlimited
5G Technology
- 5th Generation mobile network; theoretical peak speed 20 Gbps (vs. 4G's 1 Gbps)
- Latency < 1 millisecond; supports 1 million devices per km²
- Enables: autonomous vehicles, industrial IoT, smart cities, remote surgery
- India's 5G rollout began October 2022 (Airtel and Jio in 13 cities)
- 100+ cities covered by 2024
Artificial Intelligence (AI)
- Simulation of human intelligence by machines
- Machine Learning (ML): systems that learn from data
- Deep Learning (DL): neural networks with many layers; basis of image recognition and NLP
- NLP (Natural Language Processing): computers understanding/generating human language (ChatGPT, Alexa)
- Computer Vision: image/video interpretation
Big Data
- Defined by 5 Vs: Volume (terabytes to exabytes), Velocity (real-time streams), Variety (structured/unstructured text, images, video), Veracity (accuracy/trustworthiness), Value (business insights)
- Hadoop: distributed storage framework
- Apache Spark: real-time processing (100× faster than Hadoop MapReduce)
- Also uses NoSQL databases
Cloud Computing
- Delivers computing services over the Internet on a pay-per-use basis
- IaaS (Infrastructure as a Service): AWS EC2, Azure VMs
- PaaS (Platform as a Service): Google App Engine
- SaaS (Software as a Service): Gmail, Office 365
- Edge computing: processes data near its source (IoT devices, factories); reduces latency
Internet of Things (IoT)
- Network of physical objects embedded with sensors, software, and connectivity to collect and exchange data
- Examples: smart home devices (Alexa, smart thermostat), wearable fitness trackers, industrial sensors
- Smart agriculture (soil moisture sensors), connected vehicles, smart city infrastructure
- By 2025, ~75 billion IoT devices projected globally
Blockchain
- Distributed Ledger Technology (DLT): chain of blocks containing transaction records, cryptographically linked
- Replicated across a peer-to-peer network
- Decentralised: no single authority; Immutable: records cannot be altered; Transparent: all participants can verify
- Bitcoin (2009, Satoshi Nakamoto) was the first blockchain application
Digital Currency
- Cryptocurrency: decentralised, blockchain-based (Bitcoin, Ethereum); no central authority
- CBDC (Central Bank Digital Currency): government-issued digital legal tender
- India's Digital Rupee (e₹) by RBI: Wholesale e₹ pilot (November 2022), Retail e₹ pilot (December 2022)
- Unlike cryptocurrency, e₹ is centralised and backed by RBI
VR / AR / MR
- VR (Virtual Reality): fully immersive computer-generated environment via headsets (Oculus, Meta Quest, Sony PlayStation VR)
- AR (Augmented Reality): overlays digital information on real world (Pokémon Go, Google Glass, Apple Vision Pro)
- MR (Mixed Reality): blends real and digital objects that interact
- Applications: gaming, education, medical simulation, military training, tourism
OTT Platforms
- Deliver media content directly over the Internet, bypassing traditional cable/satellite TV
- India has 45+ OTT platforms; top global: Netflix (238 million subscribers), Amazon Prime, Disney+Hotstar, YouTube
- Jio Cinema: IPL 2023 — record 32 million concurrent viewers
- Regulated by MIB under IT Rules 2021
Social Media
- Web-based platforms allowing creation, sharing, and exchange of user-generated content
- Major platforms: Facebook (3.05 billion MAU), YouTube (2.5 billion), WhatsApp (2 billion), Instagram (2 billion), TikTok (1.5 billion), Twitter/X (250 million)
- India has 500 million+ social media users (2024)
- IT (Intermediary Guidelines and Digital Media Ethics Code) Rules 2021 governs social media intermediaries in India
Machine Learning Types
- Supervised Learning: learns from labelled examples (spam detection, image classification, price prediction)
- Unsupervised Learning: finds patterns in unlabelled data (customer segmentation, anomaly detection)
- Reinforcement Learning: agent learns by trial and error with rewards/penalties (AlphaGo, robotics, self-driving cars)
Generative AI (GenAI)
- AI systems that create new content: text, images, music, code, video
- Key models: GPT-4 (OpenAI), Gemini (Google DeepMind), Claude (Anthropic), Llama (Meta)
- Image generation: Stable Diffusion, DALL-E, Midjourney
- ChatGPT reached 100 million users in 60 days (November 2022) — fastest-growing consumer app in history
Quantum Computing
- Uses quantum bits (qubits) exploiting superposition and entanglement
- Potential to break current RSA encryption (Shor's algorithm) → driving post-quantum cryptography
- Applications: drug discovery, financial optimisation, climate modelling, AI acceleration
- IBM Quantum Eagle (2021): 127 qubits; IBM Condor (2023): 1,121 qubits
