Information & Communication Technology (ICT)

This is the single highest-yield table in Unit 8. Learn the expansion and the one-line function, because the examiner asks both ways: "GUI stands for …" and "Which of these allows a user to interact through icons and windows?"

The internet is a global public "network of networks" using the TCP/IP suite, owned by nobody. Its Indian ancestry matters for one factual question: the internet grew out of the American ARPANET (1969), and commercial internet service began in India on 15 August 1995 through VSNL.

• E-mail structure. An address has the form username@domain (the "@" separates the two). The To field carries the primary recipient, CC an open copy, BCC a hidden copy; Subject summarises; attachment carries files; Reply goes to the sender, Reply All to everyone in To and CC (never to BCC), and Forward sends the message onward to a new person.
• Webmail versus e-mail client. Gmail or Outlook.com in a browser is webmail — the mail lives on the server. A desktop program such as Outlook or Thunderbird is a client that fetches mail using POP3 or IMAP and sends it using SMTP.
• Audio conferencing links three or more participants by voice alone, usually over VoIP; it needs the least bandwidth and is the most robust on a weak connection. Video conferencing adds real-time two-way video, and therefore needs a camera, microphone, speaker, codec and adequate bandwidth.
• A codec (coder-decoder) compresses the audio/video for transmission and decompresses it at the other end. Latency is the delay, jitter the variation in that delay, and echo cancellation the feature that stops your own voice returning to you. Conferencing may be point-to-point (two sites) or multipoint (many sites, needing a bridge or MCU).
• Synchronous ICT tools happen live (video class, chat, webinar); asynchronous tools are time-shifted (recorded lecture, discussion forum, e-mail). Good online teaching deliberately mixes both, because asynchronous material rescues the learner with poor bandwidth.

• Input devices carry data into the machine: keyboard, mouse, trackpad, joystick, scanner, webcam, microphone, light pen, touch screen, graphics tablet, barcode/QR reader, OMR and MICR readers, biometric fingerprint and iris scanners.
• Output devices carry results out: monitor (VDU), printer, plotter, speaker, headphone, projector. Printers are impact (dot-matrix, line printer) or non-impact (inkjet, laser, thermal); a plotter draws vector line-work such as maps and engineering drawings.
• Both input and output: touch screen, modem, network interface card, headset with microphone, and any read-write storage such as a pen drive or hard disk. Examiners love asking for a device that is both, so keep touch screen and modem ready.
• Storage devices. Magnetic — hard disk drive (HDD), magnetic tape. Optical — CD (about 700 MB), DVD (about 4.7 GB single-layer), Blu-ray (about 25 GB per layer). Solid-state/flash — SSD, pen drive, memory card. And cloud storage — Google Drive, DigiLocker — where the file sits on a remote server. Storage is measured in bytes; a network connection is measured in bits per second.

A computer stores everything as 0s and 1s, so number systems appear in the syllabus. Four bases matter: binary (2) with digits 0–1, octal (8) with 0–7, decimal (10) with 0–9, and hexadecimal (16) with 0–9 and then A–F standing for 10–15. Conversion to decimal is always the same: multiply each digit by its place value and add.

1. Binary to decimal. Place values from the right are 1, 2, 4, 8, 16, 32 … So 1101₂ = (1×8) + (1×4) + (0×2) + (1×1) = 8 + 4 + 0 + 1 = 13₁₀. And 11001₂ = 16 + 8 + 0 + 0 + 1 = 25₁₀.
2. Decimal to binary. Divide repeatedly by 2 and read the remainders upwards. 25 → 12 r1, 6 r0, 3 r0, 1 r1, 0 r1 → reading up, 11001₂. Cross-check by adding the place values: 16 + 8 + 1 = 25. ✔
3. Hexadecimal to decimal. Place values are 1, 16, 256 … So 2F₁₆ = (2×16) + (15×1) = 32 + 15 = 47₁₀, and FF₁₆ = (15×16) + 15 = 240 + 15 = 255₁₀ — which is exactly the largest value one byte can hold, since 2⁸ = 256 values counted from 0.
4. Why hexadecimal exists. One hex digit equals exactly four binary digits, so long binary strings shrink fourfold: 1111 1111₂ = FF₁₆. That is why memory addresses and colour codes (#FF0000) are written in hex. ASCII uses 7 bits (128 characters, extended to 8 bits for 256), while Unicode covers the scripts of the world, which is what lets Devanagari appear on your screen at all.

This section is pure matching, and it is asked almost every year. The parent programme for most of these is the National Mission on Education through Information and Communication Technology (NMEICT), launched by the Ministry of Human Resource Development in 2009 to provide connectivity and e-content to all higher-education institutions. Learn the table as name → what it actually is, because the wrong options in the exam are always the other portals on this very list.

E-governance is the use of ICT to deliver government services, exchange information and make administration transparent and accountable. The standard formulation is that it converts government into SMART governance — Simple, Moral, Accountable, Responsive and Transparent. Its four interaction types are asked directly, so learn them by the pair of parties involved.

• Digital India was launched on 1 July 2015 by the Ministry of Electronics and Information Technology (MeitY). Its three vision areas are digital infrastructure as a utility to every citizen, governance and services on demand, and digital empowerment of citizens, delivered through nine pillars: Broadband Highways; Universal Access to Mobile Connectivity; Public Internet Access Programme; e-Governance — Reforming Government through Technology; e-Kranti (electronic delivery of services); Information for All; Electronics Manufacturing; IT for Jobs; and Early Harvest Programmes.
• DigiLocker (2015, MeitY) is a cloud-based wallet in which a citizen keeps issuer-verified digital documents — Aadhaar, driving licence, vehicle registration, school and university certificates. A document fetched into DigiLocker by the issuing authority is legally at par with the original, so no attestation is required.
• UMANG — Unified Mobile Application for New-age Governance (2017) — is a single mobile app that gathers hundreds of central and state services (EPFO, PAN, gas booking, examination results) at one place, so a citizen need not install a separate app per department.
• Aadhaar-enabled services. The UIDAI issues a unique 12-digit number with biometric de-duplication under the Aadhaar Act, 2016. It underpins e-KYC, Aadhaar-enabled Payment System (AePS), Direct Benefit Transfer (DBT) of subsidies and scholarships, and e-Sign. In examinations and admissions it is used for candidate authentication.
• Other named building blocks: NeGP (National e-Governance Plan, 2006) with its Mission Mode Projects; CSC (Common Service Centres) as village-level access points; NICNET/NIC as the government’s technical backbone; BharatNet for gram-panchayat broadband; UPI for payments; CoWIN as a large-scale service-delivery example; and NDEAR, the National Digital Education Architecture, as the framework for education-sector digital systems.

The goals of information security are summarised by the CIA triad — Confidentiality (only the authorised may read), Integrity (data are not altered without authority) and Availability (the system works when needed). Every threat and every safeguard below attacks or defends one of those three.

• Malware ("malicious software") is the family name. A virus attaches itself to a host file and needs the user to run it; a worm copies itself across a network without any user action; a trojan disguises itself as a useful program; ransomware encrypts your files and demands payment; spyware and a keylogger secretly record what you do and type; adware floods you with advertisements; a rootkit hides deep in the system; a botnet is a herd of infected machines controlled remotely.
• Phishing is a fraudulent message that impersonates a bank, university or government office to trick you into surrendering a password, OTP or card number. Its variants are spear phishing (aimed at one named person), vishing (by voice call) and smishing (by SMS). Phishing attacks the human being, not the machine — which is why no software alone can stop it.
• A firewall is the gatekeeper between a trusted internal network and the untrusted internet: it inspects traffic and permits or blocks it by rule. It may be hardware or software. It filters traffic; it does not scan files for viruses — that is antivirus software’s job.
• Encryption converts readable plaintext into unreadable ciphertext using a key. Symmetric encryption uses one shared key; asymmetric (public-key) encryption uses a public key to lock and a private key to unlock, and is what makes HTTPS, digital signatures and secure e-mail possible. A digital signature proves both the identity of the sender and that the document has not been altered.
• Other safeguards worth naming: strong and unique passwords, two-factor authentication (2FA/OTP), regular software updates and patches, backups (the 3-2-1 rule), antivirus, HTTPS-only browsing, and institutional awareness training. In India, CERT-In is the national computer emergency response team, and the Information Technology Act, 2000 (amended 2008) is the governing law.
• Netiquette (network etiquette) is the code of courteous online conduct: use a clear subject line; do not TYPE IN CAPITALS, which reads as shouting; quote only the relevant part when you reply; use BCC for a large mailing list to protect everyone’s address; never forward a chain message or a rumour unverified; respect copyright and cite sources; keep your camera and microphone discipline in a video class; and remember that anything written online is effectively permanent.