Computer Science key terms

How consistently a storage device or medium stores and retrieves data correctly over time.

The amount left over after whole-number division. When dividing by 16, the remainder is between 0 and 15.

The number of pixels an image contains, determined by its width and height in pixels.

A program’s ability to handle unexpected or invalid inputs without crashing or behaving incorrectly.

Read-only memory: primary storage that holds instructions needed to start a computer. Its contents are retained without power and are not changed during normal operation.

A device that connects different networks and forwards data packets between them towards their destinations.

Facilities that allow a program to execute, accept input and display output so that its behaviour can be tested.

An error encountered while a program is executing, such as attempting to divide by zero.

A measurement of the amplitude, or height, of a sound wave at a particular moment.

The number of samples of a sound wave taken each second, measured in Hertz (Hz).

Measuring the amplitude of an analogue sound wave at regular time intervals.

The part of a program in which a variable or constant can be accessed.

A step-by-step procedure for locating a target value in a collection of data, or determining that it is absent.

Non-volatile storage used to keep programs and data long term, including when the computer is switched off.

A programming construct that uses a condition to decide which statements to execute.

Carrying out instructions in their stated order.

Access in which data is encountered in order, so earlier sections may need to be passed before the required data can be reached.

A computer or program that provides services to clients over a network.

A component whose failure would stop the whole system from working.

Extracting a substring by specifying boundaries within a string.

Simple Mail Transfer Protocol: rules for sending email from a client to an email server and between email servers.

Manipulating people into revealing confidential information or taking actions that compromise security.

A legal agreement that sets out how software may be installed, used, copied, modified or distributed.

A solid-state secondary storage device with no moving parts, typically offering faster read/write speeds and greater resistance to knocks than an HDD.

Storage that records data electronically in non-volatile memory chips and has no moving parts, such as an SSD or USB flash drive.

A step-by-step procedure that arranges data in a specified order, such as numerical or alphabetical order.

The program instructions written by a programmer in a programming language, before translation.

Malware that secretly monitors a user's activities and collects information, such as passwords or keystrokes.

Structured Query Language: a language used to work with data in databases, including retrieving data from tables.

An attack in which malicious input is incorporated unsafely into a database query, changing what the query does.