GCE A/L General Information Technology key terms

The use of computers, networks, and digital devices to create, store, process, exchange, and communicate information. It combines computing technology with telecommunications so that data and services can be shared electronically.

Raw, unprocessed facts, figures, or symbols that have no meaning on their own until they are organised or interpreted. Examples include a list of marks or a stream of sensor readings.

Data that has been processed, organised, or interpreted so that it becomes meaningful and useful for decision-making. It is the output produced when raw data is given context.

The physical components of a computer system that can be seen and touched, such as the processor, memory modules, keyboard, monitor, and printer. Hardware executes the instructions supplied by software.

The set of programs, instructions, and associated data that tell computer hardware what to do. It includes system software such as operating systems and application software such as word processors.

The main component that fetches, decodes, and executes program instructions and controls the other parts of a computer. Its speed is commonly measured in gigahertz and it contains the control unit and arithmetic logic unit.

Volatile primary storage that holds the programs and data currently in use so the processor can access them quickly. Its contents are lost when power is switched off, which distinguishes it from secondary storage.

Non-volatile storage such as hard disks, solid-state drives, and optical discs that keeps programs and data permanently until they are deleted. It has larger capacity but slower access than main memory.

Any hardware unit that accepts data or commands from a user or the environment and converts them into a form the computer can process, for example a keyboard, mouse, scanner, or sensor.

Hardware that presents processed results to the user in a human-readable or usable form, such as a monitor, printer, speaker, or projector. Some devices, like touchscreens, act as both input and output.

System software that manages hardware resources, provides common services to applications, and offers a user interface. Examples include Windows, Linux, and Android; it controls memory, files, and processes.

A small system program that performs maintenance or housekeeping tasks, such as antivirus scanning, disk cleanup, file compression, or backup. Utilities support the operating system rather than performing user productivity work.

Software distributed with its source code freely available so anyone may inspect, modify, and redistribute it under the terms of its licence. Examples include the Linux kernel and LibreOffice.

A legal agreement that states how a program may be installed, used, copied, and distributed. It protects the developer's rights and defines what the user is permitted to do with the software.

A positional number system with base 2 that uses only the digits 0 and 1. Each position represents a power of two, and it is the natural representation of data inside digital circuits.

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

The smallest unit of digital data, representing a single binary digit that is either 0 or 1. Groups of bits encode characters, numbers, images, and instructions inside a computer.

A group of eight bits treated as a single unit of storage. One byte can represent 256 different values and is commonly used to store one character of text.

A rule that maps characters, such as letters and symbols, to numeric codes so computers can store and exchange text. Common schemes include ASCII and Unicode, which supports many writing systems.

The way numbers, text, images, sound, and video are converted into binary patterns that a computer can store and process. Different media use different encoding methods and storage sizes.

Two or more computing devices connected so they can exchange data and share resources such as files, printers, and internet access. Connections may be wired or wireless and may span small or large areas.

A network covering a limited area such as a single building or campus, usually owned and managed by one organisation. It offers high data rates and lets nearby devices share files and peripherals.

A unique numeric label assigned to each device on a network so data can be routed to it. IPv4 addresses are 32-bit; IPv6 addresses are 128-bit and greatly expand the available address space.

A distributed naming service that translates human-friendly domain names such as example.lk into numeric IP addresses. It lets users reach websites without remembering numerical addresses.

A system of interlinked documents and resources on the internet, accessed through browsers using HTTP or HTTPS. It is one service that runs on the internet, not the internet itself.

The application-layer protocol that defines how web browsers request pages and how web servers respond. Its secure version, HTTPS, encrypts the traffic using TLS to protect data in transit.

An organised collection of related data stored so it can be easily accessed, managed, and updated. Computerised databases are usually controlled by database management software.

Software that creates, stores, and controls access to a database, handling queries, security, concurrency, and recovery. Examples include MySQL, PostgreSQL, and Oracle Database.

A field or combination of fields whose value uniquely identifies each record in a table. It must be unique for every row and cannot be left empty.

A field in one table that refers to the primary key of another table, creating a link between the two. It enforces referential integrity so related records cannot point to missing data.

A database that stores data in tables made of rows and columns, with relationships expressed by shared key values. It is queried using languages such as SQL and reduces unnecessary duplication.

A standard language for defining, querying, and modifying data in relational databases. Statements such as SELECT, INSERT, UPDATE, and DELETE let users retrieve and change stored records.

A finite, ordered set of unambiguous steps that solves a problem or completes a task. An algorithm may be expressed as pseudocode, a flowchart, or a program in a programming language.

A diagram that represents an algorithm using standard symbols: ovals for start and end, parallelograms for input and output, rectangles for processes, and diamonds for decisions. Arrows show the order of execution.

A structured, English-like notation for expressing an algorithm without the strict syntax of a real programming language. It helps programmers plan logic before writing actual code.

An organised combination of people, hardware, software, data, and procedures that collects, processes, stores, and distributes information to support decision-making and operations in an organisation.

The delivery of public services and information to citizens and businesses through digital channels such as websites and mobile apps. Examples include online tax filing and digital identity services.

Buying and selling of goods and services, and related transactions, conducted over computer networks such as the internet. It includes business-to-consumer, business-to-business, and consumer-to-consumer models.

Any software written to damage, disrupt, or gain unauthorised access to a computer system, including viruses, worms, trojans, and ransomware. Protection requires updated antivirus tools and cautious behaviour.

A social-engineering attack in which a fraudster impersonates a trusted party, often by email or a fake website, to trick a victim into revealing passwords or financial details. User awareness is the main defence.

The process of converting readable data into an unreadable form using a key, so that only authorised parties can recover the original. It protects data during transmission and while stored.

Legal rights over creations of the mind, such as literary works, software, designs, and inventions. Copyright, patents, and trademarks protect owners and restrict unauthorised copying or use.

The unauthorised copying, distribution, or use of copyrighted material such as software, music, or films. It violates licence terms and intellectual property law and may expose offenders to legal penalties.

A copy of data or programs kept separately so that the originals can be restored after loss, corruption, or disaster. Regular backups to offline or remote storage reduce the risk of permanent data loss.