AQA GCSE Computer Science key terms

Software deliberately designed to damage or disrupt computer systems, steal information or carry out other harmful actions.

A recognisable pattern of code or data used by anti-malware software to identify known malware.

A name that describes the data stored in a variable or constant, or the task performed by a subroutine.

A unit of data equal to 1,000 kilobytes or 1,000,000 bytes, written MB. The prefix mega means $10^6$.

The allocation of main memory (RAM) to programs and data by the operating system.

Combining two sorted lists into one sorted list by repeatedly selecting the next value in the required order.

A sorting algorithm that repeatedly splits a list into smaller sublists, then merges sorted sublists into one sorted list.

A short, memorable name for an instruction, such as ADD for addition.

The division of a program into smaller modules, each responsible for a particular task.

An operation that returns the remainder after integer division, written as MOD in AQA pseudocode.

Running several programs over the same period, with the operating system sharing resources between them.

A loop placed inside the body of another loop.

A loop placed inside another loop. The inner loop completes each time the outer loop repeats.

A selection structure placed inside a branch of another selection structure.

A set of connected computers or other devices that can communicate and share resources.

Hardware that allows a device to connect to a network.

A set of rules governing communication between devices on a network.

Measures used to protect a computer network, its data and its resources from unauthorised access, misuse and harm.

A group of four binary digits, which can be represented by one hexadecimal digit.

A point in a tree. In a Huffman tree, a node represents either a character and its frequency or a group of characters and their combined frequency.

A general-purpose computer system designed to perform many different tasks by running different applications, rather than being built into another device for a dedicated function.

Able to retain stored data when power is removed.

Memory that retains its contents when its power supply is switched off.

Memory or storage that retains its contents when its power supply is switched off.

Typical, valid input that a program is expected to accept.

A logical operation that reverses a Boolean value: 0 becomes 1 and 1 becomes 0. Written using an overbar: $\overline{A}$.

A gate that inverts its single input: 0 becomes 1 and 1 becomes 0.