Information & Communication Technology

ICT basics & internet

A computer system has two broad parts: hardware, the physical components you can touch, and software, the programs and data that tell the hardware what to do. The central processing unit, or CPU, carries out instructions and has two main parts: the control unit, which fetches and decodes instructions and directs the flow of data, and the arithmetic logic unit, which performs arithmetic and logical operations. The CPU works with primary memory, mainly RAM, which holds the programs and data currently in use but loses its contents when the power is switched off, which is why RAM is called volatile. ROM, by contrast, retains its contents without power and holds the essential start-up instructions. Input devices, such as a keyboard and mouse, feed data in; output devices, such as a monitor and printer, present results; and secondary storage, such as a hard disk or solid-state drive, keeps data permanently.

Software divides into system software and application software. System software manages the hardware and provides the platform on which other programs run; the operating system is the chief example, managing the processor, memory, files and input and output devices, and providing the interface the user sees. Application software serves a specific user task: a word processor writes documents, a spreadsheet calculates tables, a presentation program builds slides, and a browser displays web pages. A word processor is therefore application software, not system software, a distinction the examination tests regularly.

Hardware, software and the memory hierarchy

Memory in a computer is organised as a hierarchy, trading speed against capacity and cost. At the top, closest to the CPU, are registers, tiny and extremely fast storage locations inside the processor itself, holding the data and instructions being worked on at this moment. Next is cache memory, small, fast memory that holds copies of frequently used data so the CPU need not wait for main memory. Then comes main memory, or RAM, larger and slower than cache, holding the running programs and their data. At the bottom is secondary storage, the largest and slowest layer, which keeps data when the power is off.

Memory is measured in bytes. A bit is a single binary digit, 0 or 1, and a byte is a group of 8 bits, the basic unit for a single character of text. Larger units follow powers of 1024 in the binary system used by computers: 1 kilobyte equals 1024 bytes, 1 megabyte equals 1024 kilobytes, 1 gigabyte equals 1024 megabytes, and 1 terabyte equals 1024 gigabytes. Examination questions usually test one conversion, such as how many kilobytes are in 5 megabytes, which is 5 multiplied by 1024, giving 5120 kilobytes, or how many bytes are in 2 kilobytes, which is 2 multiplied by 1024, giving 2048 bytes. The common confusion is between bits and bytes: a quantity in bits must be divided by 8 to become bytes, and a file described in megabytes is eight times larger, in bits, than the same number expressed in megabits.

Networks: LAN, MAN and WAN

A computer network connects devices so they can share data and resources. Networks are classified by the area they cover. A local area network, or LAN, covers a small area such as a room, a building or a campus. A metropolitan area network, or MAN, covers a city or a large campus spread across a city. A wide area network, or WAN, covers a large geographical area, such as a country or the world, and the internet is the largest example of a WAN.

Several devices and concepts recur in network questions. A router connects different networks and directs data between them, while a switch connects devices within a single network and forwards data to the intended device. Wireless fidelity, known as Wi-Fi, is the common wireless LAN technology, and Bluetooth is a short-range wireless technology for connecting nearby devices such as a phone and a headset. Network topology describes how devices are arranged: in a star topology every device connects to a central hub or switch, in a bus topology all devices share a single cable, and in a ring topology each device connects to two neighbours forming a loop.

The internet, the web and email

The internet and the World Wide Web are not the same thing, and the examination tests the distinction. The internet is the global network of interconnected computer networks, the infrastructure that carries data. The web is one service that runs on the internet: a system of interlinked documents and resources identified by addresses and viewed through a browser. Email, file transfer and video calling are other services on the same infrastructure. A web browser, such as a standard browser program, is software that displays web pages; a search engine is a service that indexes web pages and returns relevant results for a query. Typing a question into a browser's address bar and receiving a search results page involves both: the browser displays the page, and the search engine produced the results.

Every device on the internet is identified by an Internet Protocol address, or IP address, a numerical label that allows data to find its destination. Because numbers are hard for people to remember, the Domain Name System translates human-readable names, such as a university's website name, into IP addresses. A uniform resource locator, or URL, is the address of a specific resource, and it typically begins with a protocol such as http or https, where the s in https indicates a secure, encrypted connection. Email works on a simpler model: each address has two parts separated by the at sign, the username identifying the mailbox and the domain identifying the mail service. Sending a message uploads it from the sender to a mail server, and reading a message downloads it from the server to the reader's device; uploading means sending data from your device to a remote system, and downloading means receiving data from a remote system onto your device.

E-governance

E-governance is the use of information and communication technology to deliver government services, exchange information and improve the working of government. It is broader than simply putting a form online. Its standard models describe who interacts with whom: government to citizen, as in online certificates, fee payment and information services; government to business, as in licences and tax filing; government to government, as in data sharing between departments; and government to employee, as in internal service records. The benefits claimed for e-governance are transparency, because a citizen can track an application instead of depending on an intermediary; speed, because a service that once took a visit and a queue can be completed remotely; reduced cost and paperwork; and wider reach, because a service hosted online is available beyond office hours and beyond the district headquarters.

The examination also expects awareness of the limits, which are as examinable as the benefits. E-governance depends on connectivity, devices, digital literacy and trust: citizens without internet access or the skills to use an online service can be excluded, which is one aspect of the digital divide. Services must also protect personal data and remain available in local languages and through assisted channels, such as service centres, for those who cannot use them directly. The key idea to carry into the examination is that e-governance is a change in how services are delivered and monitored, not merely a change in the medium: the same application, submitted online, can be tracked, audited and delivered faster, and that accountability is the point, rather than the website itself.

Digital initiatives in higher education

India's digital initiatives in higher education aim to make quality learning material and library resources available to students regardless of their institution's location or resources. The best-known initiative is SWAYAM, a national platform that hosts online courses prepared by faculty from across the country, covering school, undergraduate and postgraduate levels, with video lectures, reading material, discussion forums and assessments. Closely related is the idea of a Massive Open Online Course, or MOOC: a course delivered online, open to large numbers of learners, typically with video lectures and assignments, and designed to scale far beyond a single classroom. SWAYAM is India's national MOOC platform, and a MOOC is the general course format it uses. Learning in a MOOC is usually asynchronous, meaning learners do not all study at the same time, in contrast to synchronous learning, such as a live video class, where teacher and learners are present together. A blended model combines face-to-face teaching with online material.

A second pillar is the digital library. The National Digital Library of India, often shortened to NDLI, is a single-window platform that brings together learning resources from many institutions and libraries: books, articles, theses, lecture material and other academic content, searchable through one interface. Its purpose is to reduce the gap between a well-stocked central university library and a small college library, by giving every learner access to a shared collection. Teachers should also know the concept of open educational resources: teaching and learning materials released under licences that permit free use, adaptation and sharing, which is the principle that allows platforms to share content legally at scale.

Other initiatives complete the picture. The National Programme on Technology Enhanced Learning, known as NPTEL, provides engineering and science courses, originally from the Indian Institutes of Technology, in video and web formats, and is a major source of SWAYAM courses. Virtual laboratories let students perform simulated experiments online, which matters for institutions that lack expensive equipment. A learning management system, such as the platforms colleges use to host course material, assignments and quizzes, is the institutional counterpart of these national platforms: where SWAYAM and NDLI are national resources, a learning management system is the college's own digital classroom. UGC NET questions on this topic typically ask what an initiative provides, or match an acronym to its purpose, so the reliable preparation is one precise sentence per initiative: what it is, whom it serves, and what kind of resource it offers.

Memory units and the memory hierarchy

Confusable ICT pairs

Digital initiatives: what each provides