Kerala Plus Two Computer Applications (DHSE) key terms

The smallest unit of data in computing, holding exactly one of two values, 0 or 1. Combinations of bits form larger units such as bytes, and bit depth determines how many distinct values can be stored.

A group of eight bits treated as one unit. One byte can represent 256 different values, enough for a single ASCII character, and bytes are the standard unit for measuring memory and file size.

A base-2 positional number system using only the digits 0 and 1, where each place value is a power of two. Computers use it because digital circuits have two stable states, on and off.

A base-16 number system using digits 0-9 and letters A-F. It is widely used as shorthand for binary because each hex digit maps exactly to four bits, making long bit patterns easier to read.

American Standard Code for Information Interchange, a character encoding that assigns numeric codes to letters, digits and symbols. Standard ASCII uses 7 bits per character, giving 128 codes, and remains the base of many modern encodings.

A universal character encoding standard that assigns a unique code point to characters of almost every writing system. It solves the limitation of ASCII, which covers only English and a few symbols, and supports Malayalam and other scripts.

A finite, ordered set of unambiguous steps that solves a problem or completes a task, always terminating after a limited number of operations. Algorithms are independent of any programming language and can be expressed as pseudocode or flowcharts.

A diagram that represents an algorithm using standard symbols such as ovals for start and end, parallelograms for input and output, rectangles for processes and diamonds for decisions, with arrows showing the order of execution.

A structured, English-like description of an algorithm that borrows keywords from programming, such as READ, IF and WHILE, without following the strict syntax of any real language. It helps plan logic before coding.

A translator program that converts an entire source program into machine code before execution, producing an object file. It reports all syntax errors together and the compiled program usually runs faster than an interpreted one.

A translator that reads a source program line by line, converting and executing each statement immediately. It stops at the first error it meets and needs the source code present every time the program runs.

A translator that converts assembly language, which uses mnemonics such as ADD and MOV, into machine code. It is associated with low-level programming, where each instruction usually corresponds closely to one processor operation.

The binary instruction set that a processor executes directly, written as patterns of 0s and 1s. It is the only language hardware understands, so every high-level program must eventually be translated into it.

System software that manages hardware resources such as processor time, memory and disk storage, and provides services to application programs. It offers a user interface and controls file systems, devices and process scheduling.

A small software component that lets the operating system communicate with a specific hardware device, translating general commands into the signals that device understands. Printers, graphics cards and network adapters each need one.

A category of programs that help maintain and protect a computer system, such as antivirus tools, disk defragmenters, backup programs and file compression utilities. They support the operating system rather than performing user application work.

A set of agreed rules and conventions that governs how data is exchanged between devices on a network, covering message format, timing and error handling. Without shared protocols, machines from different vendors could not communicate.

A unique numeric label assigned to each device on a network so data can be routed to it. IPv4 addresses are 32-bit numbers written as four dotted decimal octets, while IPv6 uses 128 bits.

The physical or logical arrangement of devices and links in a network, such as star, bus, ring or mesh. The choice affects cost, reliability and how easily faults can be isolated and repaired.

Local Area Network, a network covering a small area such as a room, building or campus, usually owned by one organisation. It offers high data rates and low delay, and is commonly built with Ethernet switches or Wi-Fi.

Domain Name System, the distributed naming service that translates human-readable domain names such as example.com into IP addresses. It works like a telephone directory for the internet and relies on a hierarchy of name servers.

Uniform Resource Locator, the address that identifies the location of a resource on the web. It typically contains a scheme such as https, a host name, an optional path and a query string.

HyperText Transfer Protocol, the request-response protocol used by web browsers and servers to exchange web pages and other resources. It defines methods such as GET and POST and status codes such as 404.

HyperText Markup Language, the standard language for describing the structure of web pages using elements enclosed in tags. Browsers parse it to build the page, and CSS is then applied for presentation.

Cascading Style Sheets, a language that controls the appearance of HTML documents, including colour, fonts, spacing and layout. Rules can be placed inline, in a style element or in an external file linked to the page.

A column or minimal set of columns whose values uniquely identify each row in a table. It must be unique and cannot be null, and it is used to enforce entity integrity and to link tables through foreign keys.

A column or set of columns in one table that refers to the primary key of another table, creating a relationship between them. It enforces referential integrity by rejecting values that do not exist in the referenced table.

Any column or minimal combination of columns that could serve as the primary key because its values are unique and never null in a relation. One candidate key is chosen as primary and the rest become alternate keys.

A database rule stating that every value of a foreign key must either match an existing primary key value in the referenced table or be null. It prevents orphan records and keeps relationships consistent.

The process of organising tables to reduce redundancy and avoid insertion, deletion and update anomalies, usually by applying a series of normal forms. Each step removes certain types of dependency between attributes.

Structured Query Language, the standard language for defining, manipulating and querying relational databases. Statements are grouped into DDL for structure, DML for data and DCL for permissions, with SELECT used for retrieval.

The address of a cell in a spreadsheet, formed from its column letter and row number, such as B4. A dollar sign fixes a column or row, making the reference absolute when a formula is copied.

An expression entered in a spreadsheet cell that begins with an equals sign and calculates a value from constants, cell references and operators. It recalculates automatically when the cells it depends on change.

A built-in spreadsheet routine that performs a calculation on supplied arguments and returns a result, such as SUM, AVERAGE, IF or COUNT. Functions can be nested to build more complex calculations.

A presentation template that stores the design, fonts, colours and placeholder positions applied to all slides that use it. Editing the slide master updates every dependent slide at once, keeping a deck consistent.

A visual effect applied to how one presentation slide changes to the next during a slide show, such as a fade or wipe. It affects whole slides, unlike animation, which affects objects within a slide.

An effect that controls how individual objects, such as text boxes or images, appear, move or disappear on a presentation slide. It is used to direct audience attention and should support, not distract from, the message.

A word processing feature that combines a main document containing fixed text with a data source of records to produce many personalised copies, such as letters or certificates. Placeholders in the main document are replaced by field values.

A social engineering attack in which a fraudulent message, often an email or fake website, tricks a user into revealing passwords, card numbers or other sensitive data. It exploits trust rather than technical flaws, so user awareness is the main defence.

Any software written to harm or gain unauthorised access to a system, including viruses, worms, trojans, ransomware and spyware. Protection relies on updated antivirus software, patched systems and cautious handling of downloads and attachments.

A hardware or software barrier that inspects network traffic and allows or blocks packets according to configured rules. It helps protect a private network from unauthorised access while still permitting approved services.

A legal right that gives the creator of an original work control over its copying, distribution and adaptation for a fixed period. Software, images and text found online remain protected unless a licence states otherwise.

Presenting another person's words, ideas, code or work as one's own without proper acknowledgement. In academic and professional settings it is treated as a serious ethical and often disciplinary offence.

Software released under a licence that lets anyone run, study, modify and redistribute it, with source code available. Examples include the Linux kernel and LibreOffice, and such licences work within copyright law rather than against it.

The gap between people who have affordable access to digital technology and the skills to use it and those who do not. It affects education, employment and access to government and banking services, and is a major concern in ICT policy.