Premium exam-focused revision notes on ICT terminology, computer and network basics, Internet, e-mail, conferencing, Indian digital initiatives and e-governance.
यह unit रटने के लिए नहीं—device से data, data से network, network से services और services से governance तक पूरा system समझने के लिए है।
Technology becomes useful when information moves with purpose
Computing systems used to process, store and manage information.
Networks and media that transmit voice, text, image, video and data.
The integration of both—devices, software, networks, content, people and processes.
ICT = information को बनाना, संभालना और पहुँचाना—तीनों।
| Strength | Risk / condition |
|---|---|
| Access, speed, scale and collaboration | Digital divide, accessibility and affordability |
| Automation and data-informed decisions | Privacy, surveillance, bias and poor-quality data |
| Flexible multimedia learning | Distraction, screen fatigue and weak pedagogy |
| Remote services and transparency | Cybersecurity, outage and exclusion |
Every digital object ultimately becomes patterns of bits
2 से divide करते जाएँ; remainders को नीचे से ऊपर पढ़ें।
Binary digit: 0 or 1; smallest data unit.
4 bits.
8 bits; common addressable unit.
Processor-sized group of bits; size depends on architecture.
| Exam convention | Value | Modern precise binary term |
|---|---|---|
| 1 KB | 1024 bytes | 1 KiB |
| 1 MB | 1024 KB | 1 MiB |
| 1 GB | 1024 MB | 1 GiB |
| 1 TB | 1024 GB | 1 TiB |
Input → processing → output, supported by memory and storage
Arithmetic and logic operations: addition, comparison, AND/OR/NOT.
Coordinates fetch–decode–execute and directs other components.
Tiny, fastest CPU storage holding immediate instructions/data.
| Component | Role | Exam cue |
|---|---|---|
| Motherboard | Main circuit board connecting components | System board |
| System bus | Data, address and control pathways | Communication inside computer |
| Clock | Synchronizes operations | Frequency measured in hertz |
| GPU | Parallel graphics/general computation | Graphics Processing Unit |
Classify by direction of data flow
Keyboard, mouse, touchpad, scanner, camera, microphone, biometric sensor, barcode/QR reader, OCR, OMR, MICR.
Monitor, projector, printer, plotter, speaker, headphones and haptic devices.
| Technology | Reads | Typical use |
|---|---|---|
| OCR | Printed/handwritten character images → editable text | Digitizing documents |
| OMR | Dark marks at fixed positions | Objective answer sheets |
| MICR | Magnetic-ink characters | Cheque processing |
| Barcode / QR | Machine-readable coded pattern | Items, links, IDs |
Speed, cost and capacity trade off
| Memory | Volatile? | Key fact |
|---|---|---|
| RAM | Yes | Read/write working memory; contents lost without power |
| SRAM | Yes | Faster/costlier; commonly used for cache |
| DRAM | Yes | Needs refresh; common main memory |
| ROM | No | Stores stable instructions/firmware |
| PROM | No | Programmable once |
| EPROM | No | Erased using ultraviolet light |
| EEPROM | No | Electrically erasable/reprogrammable |
| Flash | No | Block-erasable EEPROM family; SSD/USB storage |
Operating system mediates user, applications and machine
OS, drivers, utilities and language translators that run/manage the system.
Programs for user tasks: word processor, browser, spreadsheet, LMS.
Software stored in non-volatile memory controlling embedded hardware.
| Translator | Input | Typical behavior |
|---|---|---|
| Assembler | Assembly language | Converts mnemonics to machine code |
| Compiler | High-level source | Translates program to target/executable form before execution |
| Interpreter | High-level source | Executes via ongoing translation/evaluation |
Learn by family, not an alphabet dump
Central Processing Unit; Arithmetic Logic Unit; Control Unit; Random Access Memory; Read-Only Memory; Operating System; Graphical User Interface; Basic Input/Output System.
Scope, architecture and topology
Personal Area Network; a few metres around a person.
Local Area Network; building/campus/local site.
Metropolitan Area Network; city-scale.
Wide Area Network; large geographic area.
Shared backbone; break can disrupt segment.
Central device; easy isolation, central point critical.
Closed loop; data follows ring path.
Multiple paths; resilient but complex/costly.
| Device | Primary function |
|---|---|
| Hub | Repeats incoming signal to all ports; no intelligent forwarding |
| Switch | Forwards frames within LAN using MAC addresses |
| Router | Routes packets between networks using IP addresses |
| Modem | Modulates/demodulates for communication medium/access link |
| NIC | Network Interface Card/controller connects device to network |
Access policy defines the network context
Open network of interconnected networks using the TCP/IP suite. Anyone with suitable connectivity may access public services, subject to service controls.
| Feature | Internet | Intranet | Extranet |
|---|---|---|---|
| Users | General/public | Authorized members of organization | Organization + selected outsiders |
| Scope | Global | Internal/private | Controlled external collaboration |
| Example | Public university website | Employee/student internal portal | Vendor/research-partner portal |
| Control | Distributed across providers | Organization-managed | Organization-managed permissions |
The Web is one service running over the Internet
How to access: https.
Human-readable host identity resolved by DNS.
Resource location on the host.
Parameters sent to the application.
| Term | Meaning | Do not confuse with |
|---|---|---|
| Web page | Single hypertext document/resource | Whole website |
| Website | Collection of related web pages/resources | Web server |
| Browser | Client software that requests/renders web content | Search engine |
| Web server | Serves web resources over HTTP(S) | User’s browser |
| Search engine | Crawls/indexes and retrieves web information | The Internet itself |
Mostly read/static publishing.
Participation, platforms, user-generated content.
Ambiguous label; often semantic/intelligent or decentralized visions.
Different protocols solve different communication jobs
| Protocol / term | Main job | Exam memory cue |
|---|---|---|
| IP | Addressing and routing packets | Where packets go |
| TCP | Reliable, ordered, connection-oriented delivery | Accuracy/sequence |
| UDP | Connectionless datagrams with low overhead | Speed; app handles loss |
| DNS | Maps domain names to network information such as IP addresses | Internet phonebook analogy |
| DHCP | Dynamically assigns network configuration | Gets an IP automatically |
| HTTP | Web request/response protocol | Hypertext transfer |
| HTTPS | HTTP protected by TLS | Encrypted + authenticated channel |
| FTP | File transfer | Classic file protocol |
| SFTP | Secure file transfer over SSH | Not simply “secure FTP mode” |
32-bit addressing; dotted decimal such as 192.0.2.1.
128-bit addressing; vastly larger space, hexadecimal notation.
Message anatomy plus the invisible protocol team
Simple Mail Transfer Protocol moves outgoing mail from client to server and between mail servers. Think S = Send.
Carbon Copy: recipients visible to all; informational audience.
Blind Carbon Copy: addresses hidden from other recipients; useful for privacy in mass mail.
Check sender/domain, urgency, link destination, attachment and requests for credentials/OTP.
Real-time communication is a network performance problem too
End-to-end delay creates awkward pauses and people speaking over one another. Reduce network path/congestion; audio often remains usable before video.
| Mode | Media | Best use | Limitation |
|---|---|---|---|
| Audio conference | Voice | Low-bandwidth discussion | Few non-verbal cues |
| Video conference | Voice + moving image | Visual demonstrations/presence | Higher bandwidth/device demand |
| Web conference/webinar | Audio/video + screen/chat/polls | Presentation and interaction | Can become one-way; platform access |
| Asynchronous recording | Recorded media | Flexible replay | No immediate dialogue |
Encodes/compresses and decodes media for transmission/playback.
Voice over Internet Protocol carries voice as IP data.
Headset, mute discipline, captions, agenda, consent for recording and backup channel.
Security is confidentiality, integrity and availability
Only authorized people can access information.
Data remains accurate and unauthorized changes are detectable.
Authorized users can access systems when needed.
| Threat | Defining clue |
|---|---|
| Virus | Attaches to host file/program and spreads when executed |
| Worm | Self-propagates across networks |
| Trojan | Disguises malicious function as legitimate software |
| Ransomware | Blocks/encrypts data and demands payment |
| Spyware | Secretly observes/collects user information |
| Phishing | Fraudulent message/site seeks credentials or action |
| Spear phishing | Targeted, personalized phishing |
Open the organization’s known website/app independently or verify through a trusted channel. Inspect the full domain—not just display text.
Technology should expand learning—not merely digitize lectures
Learning supported/delivered through electronic technologies.
Designed integration of face-to-face and online learning.
Massive Open Online Course; scalable online participation.
Learning Management System organizes content, activity, assessment and records.
| Dimension | Option A | Option B |
|---|---|---|
| Time | Synchronous: same-time interaction | Asynchronous: flexible-time participation |
| Place | On-site | Remote/online |
| Access | Closed institutional course | Open course/resource |
| Control | Teacher-paced | Learner/self-paced |
Open Educational Resources carry permissions for reuse/adaptation under an open licence—not simply “free to view.”
Gaps in device, connectivity, affordability, accessibility, language, skill and meaningful use.
Captions, transcripts, alt text, keyboard access, readable contrast and downloadable/low-bandwidth options.
Courses, television, labs and open skill ecosystems
Four quadrants: video lecture, downloadable reading material, self-assessment tests/quizzes and online discussion forum. Multiple national coordinators serve different sectors.
Online courses/MOOCs; four-quadrant design; credit-related use subject to regulations/institution.
Group of DTH channels telecasting educational programmes 24×7; also online archive/schedule.
IITs/IISc-led technology-enhanced learning; SWAYAM coordinator for engineering.
Open-access postgraduate e-content under NME-ICT; executed by UGC/INFLIBNET.
Remote/simulation-based access to laboratory learning and experiment resources.
Open-source software education and self-learning IT skill tutorials, associated with IIT Bombay/NME-ICT.
Find resources, researchers, theses, journals and verified records
National Digital Library of India: integrated discovery/access to learning resources across levels and disciplines; implemented by IIT Kharagpur.
Consortium for higher-education e-resources; merged earlier consortia/services including UGC-INFONET, N-LIST and INDEST-AICTE.
One Nation One Subscription: country-wide access to international scholarly journals for eligible government HEIs and central R&D institutions.
INFLIBNET open repository of Indian electronic theses and dissertations.
Expert database and national researchers network; profiles expertise and scholarship.
Digital issue, access and verification of authentic academic awards/credentials.
Academic Bank of Credits supports accumulation, transfer and redemption of academic credits under applicable rules.
Permanent student identity connecting academic records; integrates DigiLocker and ABC functions.
AISHE collects higher-education statistics; NIRF is the national institutional ranking framework.
Technology enables governance; institutions determine its quality
Government to Citizen: certificates, taxes, benefits, grievance status.
Government to Business: licences, filings, procurement, compliance.
Government to Government: interdepartmental data/process coordination.
Government to Employee: payroll, leave, service records and training.
Integrated records, automation, online payment, status tracking and once-only data capture can reduce time, travel and duplication—when processes are redesigned rather than merely scanned.
Convenience without rights is not good governance
Open-source/open-standards-enabled platform tailored to HEIs for planning, administration and services—from admission and examination to employee, finance and records workflows.
Accessible? Secure? Minimal data? Transparent rule? Appeal channel? Audit trail? Human help? Offline alternative for exclusion risk?
| Challenge | Design response |
|---|---|
| Digital divide | Assisted access, multilingual/accessible design, low-bandwidth and offline channel |
| Privacy/surveillance | Purpose limitation, data minimization, consent/legal basis, retention control |
| Cyberattack/outage | Secure architecture, MFA, backup, monitoring, incident/continuity plan |
| Siloed systems | Standards, interoperability, clean master data and accountable sharing |
| Algorithmic error/bias | Validation, explainability, human review and appeal |
| Low trust | Status tracking, reasoned decisions, audit logs and grievance redressal |
Answer before inspecting the highlighted key
Binary → hardware → memory → software.
Scope → Web → protocols → mail → conferencing.
Digital education → governance → trust.
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