Computer Science key terms

The process of removing unnecessary details from a problem while retaining the essential features needed to solve it.

Permissions specifying which resources a user may access and which actions they may perform.

A variable that stores a running total as successive values are added to it.

A register that stores the results of calculations performed by the ALU.

The output or behaviour observed when a test is carried out.

A step-by-step set of instructions for completing a task.

Unfairness in the results produced by an algorithm, which can lead to some people or groups being disadvantaged.

The process of developing precise, step-by-step instructions to solve a problem.

The height of a sound wave measured from its central position.

A signal that varies continuously rather than consisting of separate digital values.

The process of converting a continuously varying analogue signal into digital values that a computer can represent in binary.

A logical operator that produces 1 only when both inputs are 1.

A logic gate whose output is 1 only when both inputs are 1.

Software that detects malicious software and can block, quarantine or remove it.

Writing additional data at the end of a file without erasing its existing contents.

An actual value or variable supplied to a subprogram when it is called.

The CPU component that performs arithmetic calculations and logical operations, including comparisons.

An operator that performs a numerical calculation, such as addition or multiplication.

An ordered, fixed-length collection of elements of the same data type, accessed using indices.

Ordering values from smallest to largest, or words alphabetically from A to Z.

American Standard Code for Information Interchange: a character set whose original 7-bit codes represent 128 characters. OCR exam questions use 8-bit binary representations of ASCII.

An instruction that stores a value under a name, usually by evaluating an expression on the right and storing its result in the variable on the left.

Checking a user's claimed identity, for example by checking that their username exists and that the supplied password matches that account.

The maximum amount of data that can be transferred over a network connection per second, measured in bits per second.

A base-2 number system that uses only the digits 0 and 1.

A pattern of bits, using only 0 and 1, that represents a value such as a pixel’s colour.

A searching algorithm that compares the target with the middle item of a sorted search range, then repeatedly searches only the half that could contain the target.

An operation that moves every bit in a binary number the same number of positions left or right.

Basic Input Output System: firmware stored in ROM that checks and initialises hardware and begins the process of loading the operating system.

A binary digit with a value of either 0 or 1.