GCE A/L Information & Communication Technology key terms

Raw, unprocessed facts and figures such as numbers, text or measurements that on their own carry little meaning until they are organised, interpreted or analysed to produce useful information.

Data that has been processed, organised or interpreted so it becomes meaningful and useful for decision-making, for example a monthly sales total derived from individual transaction records.

The gap between people or communities who have reliable access to computers, the Internet and digital skills and those who do not, often widening existing social and economic inequalities.

A base-2 positional number system that uses only the digits 0 and 1, where each position represents a power of two; it is the native representation used by digital circuits and memory.

A base-16 number system using digits 0-9 and letters A-F, widely used as a compact shorthand for binary values because one hexadecimal digit maps exactly to four binary bits.

A method of representing signed integers in binary where the most significant bit indicates the sign, and negative values are formed by inverting all bits of the positive value and adding one.

An error condition that occurs when the result of an arithmetic operation is too large or too small to be stored in the fixed number of bits allocated to it, producing an incorrect value.

A character encoding standard that assigns 7-bit numeric codes to letters, digits, punctuation and control characters, enabling computers to store and exchange text consistently.

A universal character encoding standard that assigns a unique code point to characters of virtually every writing system, supporting multilingual text where ASCII alone is insufficient.

The process of reducing the size of a file or data stream by encoding it more efficiently, saving storage space and transmission time; it may be lossless or lossy.

A branch of mathematics dealing with variables that take only two values, true or false, using operators such as AND, OR and NOT; it provides the theoretical basis for designing logic circuits.

A physical electronic component that performs a basic Boolean operation such as AND, OR, NOT, NAND or XOR on one or more binary inputs to produce a single binary output.

A table listing every possible combination of input values for a logic circuit or Boolean expression together with the resulting output, used to analyse or verify circuit behaviour.

A small, very fast storage location inside the CPU used to hold data, instructions or addresses temporarily while an operation is being carried out.

A small, high-speed memory located close to or inside the processor that stores frequently used instructions and data to reduce average access time to main memory.

A technique in which part of secondary storage is used as an extension of RAM, allowing programs larger than physical memory to run, at the cost of slower access.

System software that manages hardware resources, provides services to application programs and offers a user interface, controlling memory, processes, files and input/output devices.

A category of system software designed to maintain, protect or optimise a computer system, for example antivirus tools, disk defragmenters, backup programs and file compressors.

A formally agreed set of rules and conventions governing how devices exchange data over a network, covering message format, timing, addressing and error handling.

A seven-layer reference model describing network communication from physical transmission up to application services, used to standardise and explain how protocols cooperate.

The core suite of protocols used on the Internet, in which IP handles addressing and routing of packets while TCP provides reliable, ordered delivery of data streams.

A unique numerical label assigned to each device on a network so that data packets can be addressed and routed to the correct destination.

The Domain Name System, a distributed naming service that translates human-readable domain names into IP addresses so browsers can locate web servers.

A transmission technique in which data is divided into small packets that travel independently across a network and are reassembled at the destination, improving network efficiency.

The maximum rate at which data can be transmitted over a communication channel, usually measured in bits per second, determining how quickly files can be transferred.

A Uniform Resource Locator, the standardised address that identifies the location of a resource on the web, specifying the protocol, domain name and path.

The Hypertext Transfer Protocol, a request-response protocol used by web browsers and servers to transfer web pages and other resources across the Internet.

Hypertext Markup Language, the standard language used to structure web page content through elements and tags such as headings, paragraphs, links and images.

The buying and selling of goods and services, and the transfer of money and data, over electronic networks such as the Internet, including business-to-consumer and business-to-business models.

The delivery of public services and information to citizens and businesses through digital channels such as websites and online portals, improving convenience and transparency.

An organised collection of related data stored so it can be easily accessed, managed and updated, typically structured into tables, records and fields under a database management system.

A field or combination of fields that uniquely identifies each record in a database table and cannot contain duplicate or null values.

A field in one table that refers to the primary key of another table, creating a link between the tables and enforcing referential integrity in a relational database.

The process of organising database tables to reduce redundancy and avoid update anomalies by dividing data into related tables according to rules called normal forms.

A finite, unambiguous sequence of steps for solving a problem or completing a task, which can be represented as pseudocode or a flowchart before being coded.

A diagram that uses standard symbols such as ovals, rectangles and diamonds connected by arrows to represent the sequence, decisions and repetition in an algorithm.

A structured, human-readable description of an algorithm using programming-like keywords and indentation without the strict syntax of any particular language.

A defined way of organising and storing data in a computer so that it can be accessed and modified efficiently, for example arrays, linked lists, stacks, queues and trees.

A linear data structure that follows the last-in-first-out principle, where elements are added and removed only at one end, as in undo operations or function calls.

A linear data structure that follows the first-in-first-out principle, where elements are added at one end and removed from the other, as in print jobs or task scheduling.

The process of converting plaintext into unreadable ciphertext using a key and algorithm so that only authorised parties can recover the original data.

An encrypted electronic code attached to a message that verifies the sender's identity and confirms the data has not been altered in transit.

Malicious software such as viruses, worms, trojans and ransomware designed to damage, disrupt or gain unauthorised access to a computer system or its data.

A social engineering attack in which fraudulent emails or websites impersonate a trusted organisation to trick users into revealing passwords, card numbers or other sensitive data.

The delivery of computing services such as storage, processing and software over the Internet on demand, allowing users to access resources without owning the underlying hardware.

A network of everyday physical devices embedded with sensors and network connectivity that collect and exchange data, enabling remote monitoring and automation.

Extremely large and complex datasets characterised by high volume, velocity and variety, which require specialised tools and techniques to store, process and analyse.

The branch of computing concerned with building systems that perform tasks normally requiring human intelligence, such as learning, reasoning, perception and natural language understanding.

A subfield of artificial intelligence in which algorithms improve their performance on a task by learning patterns from data rather than being explicitly programmed for every case.