Computer Science key terms

A network arrangement in which each device connects directly to a central device, usually a switch.

A data structure whose size is fixed once it has been created, although its stored values may change.

The maximum amount of data a storage device or medium can hold, usually measured in bytes and their multiples.

Hardware that reads data from or writes data to a storage medium. Some devices contain their medium; others use removable media.

The physical material on which data is recorded, such as an optical disc or magnetic tape.

The principle that a program's instructions are held in memory so that the processor can fetch and execute them.

Receiving and playing audio or video as data arrives, rather than waiting for the whole file to download before playback begins.

A sequence of characters treated as text by a program, including letters, digits, punctuation and spaces.

A diagram showing how a problem is divided into subsections and how those subsections are linked.

A named section of code that performs a particular task and can be called when needed, such as a function or procedure.

A smaller part of a problem that groups related tasks.

A sequence of characters extracted from within a string.

A device that connects wired devices within a network and forwards data packets to the intended device.

An error that breaks the grammatical rules of a programming language, preventing the affected code from being run or translated.

Data organised into rows and columns within a database.

The value that a searching algorithm is trying to find.

Transmission Control Protocol/Internet Protocol: protocols that work together to provide reliable data transfer and addressing and routing across networks.

A unit of data equal to 1,000 gigabytes using the decimal convention.

An input chosen to check whether a program behaves as expected.

The process of checking a program’s behaviour against expected results to find errors and assess whether it meets its requirements.

A structured record of tests, including input data and expected results, used to check whether an algorithm or program meets its requirements.

A table used to follow an algorithm step by step, recording variable values and any inputs, outputs or condition results needed to show its execution.

Accepting a limitation in one feature to gain a benefit in another, such as accepting less image detail to reduce file size.

An electronic component that can act as a switch. In computer processing circuits, its two switching states allow binary data to be represented.

Software that translates program source code into machine code so that its instructions can be executed by a processor.

The physical or wireless means by which data signals travel between network devices, such as copper cable, fibre-optic cable or radio waves.

Malware disguised as legitimate software to persuade a user to install or run it.

A table showing every possible combination of Boolean inputs and the corresponding output.

A collection of elements arranged in rows and columns, in which two indices identify an element.

A check that input is of, or can be interpreted as, the required data type.