NIELIT CCC key terms

The main chip that fetches, decodes and executes program instructions, performing arithmetic, logic and control operations. It is often called the brain of the computer and works with memory and storage.

The part of the CPU that carries out arithmetic operations such as addition and subtraction and logical comparisons such as AND, OR and greater-than. Results are passed back to registers or memory.

Volatile main memory that holds programs and data currently in use so the CPU can read and write them quickly. Its contents are lost when power is switched off.

Non-volatile memory whose contents are retained without power and normally cannot be changed by ordinary programs. It stores firmware such as the BIOS or boot instructions needed at startup.

A small, very fast memory placed close to the CPU that keeps frequently used instructions and data. It reduces the time the processor waits for slower main memory.

A tiny high-speed storage location inside the CPU used to hold the current instruction, operands and intermediate results during processing. Registers are the fastest storage in a computer.

Basic Input Output System: firmware stored in ROM that runs when a computer is switched on, tests hardware and locates a bootable device so the operating system can load.

Hardware used to enter data and commands into a computer, such as a keyboard, mouse, scanner, microphone or touchscreen. It converts human actions into signals the machine can process.

Hardware that presents processed results to the user, for example a monitor, printer, speaker or projector. It converts the computer's internal signals into human-readable or physical form.

Any device connected to and controlled by the computer but external to the CPU and main memory, including keyboards, printers, disks and network adapters. Peripherals are classed as input, output or storage devices.

System software that manages hardware, memory, files and processes and provides services to application programs. It offers the user interface through which the machine is controlled.

The core part of an operating system that stays in memory and directly controls hardware, scheduling, memory and device access. Applications request these services through system calls.

A user interface built from windows, icons, menus and a pointer, operated mainly with a mouse or touch. It lets users work without memorising typed commands.

A text-based interface where the user types commands and receives text output. It is compact, scriptable and often preferred for administration and automation tasks.

The method an operating system uses to name, store, organise and retrieve files on a storage device, including directories, permissions and metadata. Examples include FAT32, NTFS and ext4.

The text that specifies a file or folder location within a file system, such as C:\Users\Docs\a.txt or /home/user/a.txt. An absolute path starts from the root; a relative path starts from the current folder.

Software that lets the operating system communicate with a particular piece of hardware by translating general commands into device-specific instructions. Drivers are usually supplied by the hardware manufacturer.

The startup sequence in which hardware is tested, firmware runs and the operating system is loaded into memory so the computer becomes ready for use. A cold boot starts from power-off; a warm boot restarts.

Application software for creating and editing text documents, with formatting, tables, spell check and page layout. Files are saved in formats such as .docx, .odt or .pdf.

A named design of characters with a particular typeface, size and style such as Arial 12 bold. Fonts affect how text looks and how much space it occupies on a page.

A word-processing feature that combines one main document with a list of records to produce many personalised copies, such as letters or labels. Placeholders in the main document are filled from each record.

A pre-designed document or file used as a starting point that already contains layout, styles and placeholder content. Saving as a template lets the same structure be reused without rebuilding it.

Application software that organises data in a grid of rows and columns of cells and recalculates results when values change. It is used for calculations, charts, lists and simple databases.

The address of a cell in a spreadsheet, formed from its column letter and row number, such as B7. A dollar sign before a part makes it absolute, as in $B$7.

An expression entered in a spreadsheet cell that begins with = and calculates a value from numbers, cell references and operators. Results update automatically when the referenced cells change.

A built-in named calculation in a spreadsheet, such as SUM, AVERAGE, IF or COUNT, that takes arguments and returns a result. Functions save writing long formulas by hand.

Application software for building a sequence of slides containing text, images, charts and multimedia, shown as a slide show. Files are typically saved as .pptx or .odp.

The top-level slide that stores the design, fonts, colours and placeholder positions applied to all slides in a presentation. Editing it changes the look of every slide that follows it.

The visual effect played when moving from one slide to the next during a slide show, such as a fade or wipe. It differs from animation, which affects objects within a single slide.

An effect applied to text, images or other objects on a slide to control how they appear, move or disappear. Animations are set per object, unlike slide transitions.

A worldwide network of interconnected computer networks that exchange data using the TCP/IP protocol suite. It carries services such as the web, email and file transfer.

A collection of linked documents and resources accessed over the Internet using HTTP or HTTPS and identified by URLs. It is one service running on the Internet, not the network itself.

The address that identifies a resource on the web, giving the scheme, host name and path, for example https://example.com/page. It tells the browser where and how to fetch the item.

A human-readable name for an Internet host, such as example.org, made of labels separated by dots and mapped to an IP address by DNS. The rightmost label shows the top-level domain.

A numeric label assigned to a device on a network so data can be routed to it. IPv4 uses four numbers 0-255 separated by dots; IPv6 uses longer hexadecimal groups.

The Internet service that translates human-readable domain names into IP addresses so browsers can reach servers. It works like a distributed directory of names and addresses.

Client software that requests web pages from servers using HTTP or HTTPS and renders them for the user. Examples include Chrome, Firefox and Edge; it also stores history, cookies and bookmarks.

A web service that indexes pages and returns ranked links matching a user's keywords or query. Examples include Google and Bing; operators such as quotes or site: refine results.

A small piece of data a website stores in the browser and sends back on later requests, used for sessions, preferences and tracking. Users can block or delete cookies in browser settings.

A unique identifier for an electronic mailbox, written as local-part@domain, for example [email protected]. The part before @ names the mailbox; the part after names the mail server's domain.

An email field that sends a copy of a message to additional recipients whose addresses are visible to everyone receiving the mail. It is used to keep people informed without making them primary recipients.

An email field that sends a copy to recipients whose addresses are hidden from other recipients. It protects privacy when mailing a list of people who do not know one another.

A file sent along with an email message, such as a document, image or spreadsheet. Mail servers limit attachment size, so large files are often shared by link instead.

Unsolicited bulk email, usually advertising or fraudulent, sent to many recipients without consent. Filters and spam folders move such messages out of the inbox automatically.

A fraud in which a message or fake website pretends to be a trusted organisation to trick people into revealing passwords, card numbers or other sensitive data. Checking the sender and link address helps detect it.

An online platform where users create profiles, connect with others and share posts, photos or messages. Examples include Facebook, LinkedIn and X; privacy settings control who sees content.

The accepted rules of polite and responsible behaviour in online communication, such as avoiding all-caps text, staying on topic and respecting others' privacy. It applies to email, forums and social media alike.

The delivery of government services and information to citizens, businesses and other agencies through information and communication technology, often via web portals. It aims to make services faster, transparent and more accessible.

An electronic method that uses cryptography to verify the identity of the sender and confirm that a document has not been altered. It gives electronic records legal validity in many government services.

Any illegal act committed using computers or networks, such as hacking, identity theft, online fraud or data theft. It is reported to police cyber cells and handled under laws such as the IT Act.

A Government of India programme launched in 2015 to deliver public services digitally, build digital infrastructure and improve digital literacy. It supports services such as DigiLocker, UMANG and online payments.