Computers, IT & Emerging Technologies

Computer "generations" are named after the switching device used — the thing that turns current on and off. Each new device was smaller, cooler and faster, so machines shrank from room-sized to pocket-sized. Learn the device, and the generation follows.

Software has two broad kinds. System software runs the machine itself — the operating system (Windows, Linux, Android, macOS, iOS), device drivers, and utilities. Application software does a user's job — word processor, spreadsheet, browser, payment app. The operating system is the manager in between: it allocates memory and processor time, manages files, and gives applications a common way to reach the hardware. Open-source software (Linux, LibreOffice) has freely available source code; proprietary software does not.

A computer understands only binary, so programs written in a high-level language (C, Java, Python) must be translated. A compiler translates the whole program at once into machine code and reports all errors together; the translated file then runs fast and repeatedly. An interpreter translates and executes line by line, stopping at the first error — slower to run, but easier to debug. An assembler is the special translator for assembly language.

• Text / documents: .txt (plain text), .doc/.docx (Word), .pdf (Portable Document Format — layout fixed)
• Spreadsheet / presentation: .xls/.xlsx, .ppt/.pptx
• Images: .jpg / .jpeg (compressed photos), .png (supports transparency), .gif (simple animation), .svg (vector, scalable)
• Audio / video: .mp3, .wav; .mp4, .avi, .mkv
• Compressed / web: .zip, .rar; .html, .css, .js

A network is two or more computers linked so they can share data and devices. Networks are classified by how much ground they cover: a LAN (Local Area Network) covers one building — an office or a school computer lab; a MAN (Metropolitan Area Network) covers a city; a WAN (Wide Area Network) covers regions, countries or the world. The Internet is the largest WAN — a network of networks. A PAN (Personal Area Network) is the few metres around one person, which is what Bluetooth creates.

• Topology = the shape in which computers are wired. Bus: all on one backbone cable — cheap, but one break can down the segment.
• Star: every node connects to a central hub or switch — easy to manage, but the hub is a single point of failure. Most common today.
• Ring: each node connects to two neighbours, data moves in a loop.
• Mesh: many nodes joined to many others — most reliable, most expensive.
• Tree / hybrid: a hierarchy of stars, used in large campuses.

Most of the internet works on the client–server model. Your browser or app is the client: it asks. A powerful computer somewhere else is the server: it stores the data and answers. When you open a result page, your phone (client) requests it and the commission's server sends it back. In a peer-to-peer network, by contrast, every machine is both client and server.

Every device on the internet has a numeric IP address (IPv4 uses four numbers like 192.168.1.1; the newer IPv6 is far longer and gives many more addresses). Humans cannot remember numbers, so we use domain names like bpsc.bihar.gov.in. The DNS (Domain Name System) is the internet's phone book — it converts the domain name you type into the IP address the machine needs. An ISP (Internet Service Provider) — BSNL, Jio, Airtel — is the company that connects you to the internet. Bandwidth is how much data a link can carry per second (measured in Kbps, Mbps, Gbps); more bandwidth means faster downloads.

Note the pattern: 2G digitised voice, 3G brought data, 4G made data fast, and 5G made it fast plus instant plus crowded-friendly. The big leap at 5G is not only speed but latency — the delay before a response begins.

Wi-Fi and Bluetooth are both wireless but solve different problems. Wi-Fi creates a wireless LAN — higher speed, range of roughly tens of metres, meant to connect devices to the internet through a router. Bluetooth creates a personal area network — short range (about 10 metres in common devices), low power, meant to pair two devices directly, like earphones to a phone. So: Wi-Fi for internet, Bluetooth for device-to-device.

Cloud computing means using computing power, storage and software that sit in someone else's data centre and are delivered over the internet, paid for as you use them. It comes in three service layers: IaaS (Infrastructure as a Service) gives you bare machines and storage; PaaS (Platform as a Service) gives you a ready environment to build and run your own program; SaaS (Software as a Service) gives you a finished application to simply use — Gmail, DigiLocker, Google Docs.

The Internet of Things (IoT) is the idea of giving ordinary objects sensors and a network connection so they can report data and be controlled remotely — a smart electricity meter, a soil-moisture sensor in a field, a fitness band, a traffic light that senses queues. Edge computing is the companion idea: instead of sending every reading to a distant cloud, process it on or near the device itself. This cuts delay, saves bandwidth, and keeps working when the link drops — which is exactly why it matters for a CCTV camera or a farm sensor in a village with patchy connectivity.

The commonest attacks target the person, not the machine. Phishing is a fake email, message or website that imitates a bank, a commission or a delivery company and asks you to "verify" your details. Vishing is the same fraud by voice call — someone claiming to be from your bank asks for an OTP. Smishing is by SMS. No bank, no UIDAI officer and no examination board ever asks for your OTP, PIN or password.

The defences are equally simple in principle. A firewall sits between a trusted network and the untrusted internet and filters traffic by rules — a gatekeeper checking passes. Encryption scrambles data so that only a holder of the right key can read it: in symmetric encryption both sides share one secret key; in asymmetric (public-key) encryption everyone has a public key to lock and a private key to unlock. A digital signature reverses this — the sender signs with the private key and anyone can verify with the public key, which proves both who sent it and that nothing was altered. Two-factor authentication (2FA) demands two different kinds of proof: something you know (password) plus something you have (OTP on your phone) or something you are (fingerprint).

India's primary cyber law is the Information Technology Act, 2000. It gave legal recognition to electronic records and digital signatures, made electronic filing with government valid, and defined cyber offences. It was modelled on the UNCITRAL Model Law on Electronic Commerce (1996). The IT (Amendment) Act, 2008 widened it considerably: Section 43A made body corporates liable to pay compensation for failing to protect sensitive personal data, Section 69/69A dealt with interception and blocking of content, and Section 70B gave statutory backing to CERT-In. The amendment had also inserted Section 66A on "offensive" messages, which the Supreme Court struck down as unconstitutional in Shreya Singhal v. Union of India (2015) for violating free speech.

CERT-In (Indian Computer Emergency Response Team) is the national nodal agency for responding to computer-security incidents. It works under the Ministry of Electronics and Information Technology (MeitY), issues alerts and advisories, and coordinates incident response. The Digital Personal Data Protection (DPDP) Act, 2023 is India's dedicated data-privacy law, passed after the Supreme Court held privacy to be a fundamental right in K. S. Puttaswamy (2017). Learn its vocabulary: the individual whose data it is, is the Data Principal; the entity that decides how to process it is the Data Fiduciary; processing generally needs free, informed, specific consent given for a stated purpose; and a Data Protection Board of India is to handle breaches and complaints.

The Digital India programme was launched on 1 July 2015 by the Ministry of Electronics and Information Technology. Its three vision areas are simple to remember: digital infrastructure as a utility to every citizen, governance and services on demand, and digital empowerment of citizens. These are delivered through nine pillars.

• Broadband Highways — optical fibre to villages, the core of which is BharatNet.
• Universal Access to Mobile Connectivity — covering uncovered villages.
• Public Internet Access Programme — Common Service Centres (CSCs) and post offices as service points.
• e-Governance: reforming government through technology, and e-Kranti — electronic delivery of services.
• Information for All — open data and proactive disclosure.
• Electronics Manufacturing, IT for Jobs (skilling), and Early Harvest Programmes (quick wins).

The engine of the whole edifice is identity plus payment. Aadhaar is a 12-digit unique identity number issued by the UIDAI (Unique Identification Authority of India), which was set up in 2009 and became a statutory authority under the Aadhaar Act, 2016. On top of identity sits payment: the NPCI (National Payments Corporation of India) — an umbrella organisation for retail payments promoted by the RBI and the Indian Banks' Association — launched the Unified Payments Interface (UPI) in 2016. UPI lets you pay instantly from bank account to bank account using only a virtual payment address or a QR code, at any hour, without sharing account numbers. NPCI also runs RuPay, IMPS, AEPS, NETC FASTag and the BHIM app.

Service delivery rests on a few well-known platforms. DigiLocker is a cloud locker where a citizen keeps verified documents — marksheets, driving licence, Aadhaar — legally equal to the original paper. UMANG (Unified Mobile Application for New-age Governance) puts services from many departments into one app. Direct Benefit Transfer (DBT) sends subsidies and benefits straight into the beneficiary's bank account, cutting leakages and middlemen. It is powered by the JAM trinity — Jan Dhan (an account), Aadhaar (an identity), Mobile (a way to reach you). Common Service Centres (CSCs), run by Village Level Entrepreneurs, are the human counter where a villager without a smartphone still gets these services; BharatNet is the project laying optical fibre to gram panchayats to make that possible. e-Courts has digitised case records and created the National Judicial Data Grid (NJDG), so a litigant can track a case online.

Artificial Intelligence (AI) is the attempt to make machines perform tasks that normally need human intelligence — recognising a face, translating a sentence, driving a car. Machine Learning (ML) is the main method used today: instead of being given rules, the machine is given examples and it finds the pattern itself. In supervised learning the examples are labelled (thousands of photos already marked "cat"/"not cat") and the machine learns to predict the label. In unsupervised learning there are no labels — the machine only groups similar items together (clustering). Deep learning uses many-layered artificial neural networks. Generative AI and Large Language Models (LLMs) are trained on enormous amounts of text and produce new text by repeatedly predicting the most likely next word; they are fluent but can be confidently wrong, so their output must always be verified.

India's policy response has two well-known steps: NITI Aayog's National Strategy for Artificial Intelligence (2018), whose slogan was "#AIforAll", and the IndiaAI Mission approved in 2024 under MeitY to build shared computing capacity, datasets and skills. The ethical concerns are examinable in their own right: bias (a model trained on unfair historical data repeats that unfairness), jobs (routine work is automated faster than workers can reskill), deepfakes (convincing fake audio and video that threaten elections and reputations), privacy, and the opacity of systems whose reasoning cannot be inspected.

Big Data means datasets too large and messy for ordinary tools, and it is defined by the "3 Vs": Volume (sheer quantity), Velocity (speed at which it arrives) and Variety (text, images, sensor readings, all mixed). Two more Vs are often added — Veracity (how trustworthy it is) and Value (whether it is any use). Blockchain is a distributed ledger: the same record is kept on many computers, entries are grouped into blocks and each block carries a cryptographic hash of the previous one, so altering an old entry breaks the whole chain and is immediately visible. There is no central custodian; the network agrees by consensus. Uses go well beyond money — land records, supply-chain tracking, certificates.

Quantum computing uses the rules of quantum physics to compute. An ordinary bit is either 0 or 1. A qubit can be in a superposition — a combination of 0 and 1 at the same time — so a set of qubits can explore many possibilities together, which for a few special problems (factoring large numbers, simulating molecules, some optimisation) is far faster than any classical machine. Entanglement links two qubits so that their results stay correlated no matter how far apart they are. Quantum machines are not "faster computers" for everyday work; they are specialists, and they are still fragile and error-prone. India approved the National Quantum Mission in 2023 under the Department of Science and Technology to build quantum computers, secure communication, sensing and materials.