NIELIT CCC+ key terms

The main chip that carries out instructions by fetching, decoding and executing them. It performs arithmetic, logic and control operations and is often called the brain of the computer.

Fast, volatile working memory that holds programs and data currently in use. Its contents are lost when power is switched off, so it differs from permanent storage.

Non-volatile memory whose contents are written during manufacture and normally cannot be changed by the user. It stores firmware such as the bootstrap program used at start-up.

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

Firmware stored on the motherboard that tests hardware at start-up, initialises devices and then hands control to the boot loader. Its settings include boot order and system clock.

Software permanently stored in a hardware device on a ROM or flash chip. It controls the device at a low level and is usually updated only by a special procedure.

The main circuit board of a computer that connects the processor, memory, storage and expansion cards, and provides ports for external devices. It also carries the chipset and firmware.

A storage device that keeps data in flash memory chips with no moving parts. It offers faster access and greater shock resistance than a magnetic hard disk, though usually at higher cost per gigabyte.

A magnetic storage device that writes data on rotating platters read by moving heads. It provides large capacity at low cost but is slower and more fragile than flash storage.

The start-up sequence in which the computer runs firmware checks, loads the operating system from storage into RAM and hands control to it. It may be cold (from power off) or warm (restart).

A bit is a single binary digit, 0 or 1. A byte is a group of eight bits and is the basic unit for storing one character; larger units are kilobyte, megabyte, gigabyte and terabyte.

A positional number system that uses only the digits 0 and 1, with each place value a power of two. Computers use it because circuits have two stable states, on and off.

A base-16 number system using digits 0 to 9 and letters A to F. It is used as a compact shorthand for binary values, for example in colour codes and memory addresses.

A rule that maps characters to numeric codes so they can be stored and exchanged. ASCII covers basic Latin characters, while Unicode covers scripts of most languages, including Indian scripts.

A universal character encoding standard that assigns a unique code point to characters of almost every writing system. UTF-8 is its most common byte-based form on the web.

Language translators. A compiler converts a whole source program into machine code before execution, while an interpreter translates and runs statements one at a time, which helps during development.

Source code is program text written by a person in a high-level language. Object code is the machine-oriented version produced by a compiler, which the linker turns into an executable file.

An algorithm is a finite, ordered set of steps that solves a problem. A flowchart shows the same logic pictorially with standard symbols such as process, decision and input/output boxes.

System software that manages hardware, files, memory and processes, and provides a user interface. It lets application programs run and coordinates shared resources between them.

A visual way of interacting with a computer using windows, icons, menus and a pointer device. It replaces typed commands and makes common tasks easier for non-technical users.

An interface where the user types text commands and reads text output. It is efficient for repetitive and scripted tasks but requires knowledge of command names and syntax.

A file is a named collection of stored data such as a document or image. A folder groups files and other folders, creating a hierarchy that keeps storage organised.

A path states the location of a file in the folder hierarchy, such as C:\Docs\a.txt. The extension is the suffix after the last dot that indicates the file type.

Reducing file size by encoding data more efficiently, either with lossless methods that restore the original exactly or lossy methods that discard detail. It saves storage and speeds up transfer.

A small program that lets the operating system communicate with a particular hardware device, such as a printer or graphics card. It translates general commands into device-specific instructions.

A feature in which the operating system detects newly attached hardware, loads a suitable driver and configures it automatically, so the user does not have to set jumpers or interrupt values manually.

The automatic movement of text to the next line when the current line is full, without the user pressing Enter. It keeps paragraphs tidy when margins or font size change.

The horizontal positioning of text within its margins: left, right, centre or justified. Justified text is stretched so both edges are flush, while others leave one edge ragged.

Areas at the top and bottom of each page that repeat fixed content such as page numbers, document title or date. They are edited once and apply to all pages in the section.

A word-processing feature that combines one main document with a data source to produce many personalised copies, such as letters or labels, each filled with a different record's fields.

A command that searches a document for specified text and optionally substitutes new text for every match or only selected matches, saving time on repetitive corrections.

The address of a cell formed by its column letter and row number, such as B5. A dollar sign before a part makes it absolute so it does not change when copied.

A formula is a user-written expression beginning with = that calculates from cell values. A function is a built-in routine such as SUM or AVERAGE that performs a calculation on supplied arguments.

A rectangular block of cells identified by its corner addresses, for example A1:C10. Functions and charts commonly take a range as their input instead of individual cells.

A graphical representation of worksheet data such as a column, line or pie chart. It makes trends and comparisons easier to see and updates when the underlying data changes.

A template slide that stores the layout, fonts, colours and placeholders shared by all slides in a presentation. Editing it applies consistent changes across the whole deck.

A transition is the effect shown when moving from one slide to the next. An animation applies motion or emphasis to objects within a single slide.

A numeric label assigned to a device on a network so data can be routed to it. IPv4 uses four dotted decimal numbers; IPv6 uses a longer hexadecimal form.

The internet service that translates human-readable domain names into IP addresses. Without it, users would have to remember numeric addresses for every website.

The complete address of a resource on the web, giving the protocol, domain name and path, such as https://example.com/page. It tells the browser where and how to fetch content.

The encrypted version of the web transfer protocol, using TLS to protect data between browser and server. Browsers mark such pages with a padlock and warn about insecure forms.

A special word or symbol used in a search box to refine results, such as quotation marks for an exact phrase, site: to limit to one domain, or a minus sign to exclude a word.

A small piece of data a website stores in the browser to remember state, such as a login session or language choice. Third-party cookies are widely used for tracking.

Application software that requests web pages, interprets HTML, CSS and scripts, and displays the result. It also manages bookmarks, history, downloads and security warnings.

The standard protocol for sending outgoing email from a client to a mail server and between servers. Receiving mail normally uses IMAP or POP3 instead.

A mail-access protocol that keeps messages on the server and synchronises folders and read status across devices. It suits users who check mail from several devices.

A mail-access protocol that typically downloads messages to one device and may delete them from the server. It suits single-device use but synchronises poorly across devices.

Fields that send a copy of a message to extra recipients. CC addresses are visible to everyone, while BCC addresses are hidden from other recipients, protecting their privacy.

A file sent along with a message, encoded so it survives mail transport. Size limits apply, and unexpected attachments are a common way of delivering malware.

Spoofing forges the sender address so a message appears to come from someone trusted. Phishing uses such deceptive messages to trick recipients into revealing passwords or clicking harmful links.

An encrypted checksum attached to a message or document that proves its origin and shows whether it was altered. It provides authentication and integrity, not secrecy of the content.

An electronic document issued by a certificate authority that binds a public key to an identity. Browsers use it to verify that a secure website is genuine.

An Indian instant payment system that lets users transfer money between bank accounts using a virtual payment address or mobile number, usually with a PIN confirmation.

A password valid for a single login or transaction, often sent by SMS or generated by an app. It adds a second factor beyond a static password.

An online service for storing personal documents such as certificates in digital form and sharing verified copies with requesting agencies, reducing the need for physical copies.