AQA GCSE Computer Science key terms

A standard that assigns codes to characters so that text can be represented in binary.

The collection of characters available in a character encoding system.

A device that generates regular electrical pulses to synchronise computer components.

The number of clock cycles per second, measured in hertz (Hz). The CPU’s clock provides timing signals that coordinate its operations.

Keeping data on remote servers accessed through a network, rather than only on a local device.

The number of bits in the binary code assigned to a character or other data element.

Using an existing piece of code again, elsewhere in the same program or in another program.

The number of bits used to represent the colour of each pixel.

An operation that checks two values against each other, for example to decide which comes first in sorted order.

A program that translates a whole high-level program directly into machine code before that translated program is run.

The process of reducing the size of a file so that it requires less storage space.

A group of connected devices that can exchange data.

A set of instructions written in a programming language to carry out a task, implementing one or more algorithms.

A combination of hardware and software working together.

Malware that replicates by inserting copies of itself into other files or programs and can spread when infected files are transferred and run.

Joining two or more strings in order to produce a new string.

An expression that evaluates to either True or False and can control a choice or repetition in a program.

Information that should only be available to authorised people, such as passwords or private account details.

A named value that cannot be changed once assigned during program execution.

The CPU component that decodes instructions and coordinates processing by sending control signals to other components.

A network cable that carries data using electrical signals through copper conductors.

The price of a storage device divided by its capacity in gigabytes, allowing the cost of different capacities to be compared.

Information used to gain access to a system, such as a username and password.

Information supplied to authenticate a user, such as a username and password.

The protection of computer systems, networks and data against unauthorised access, damage and other threats.

A structured, persistent store of related data; persistent means the data is retained for later use.

Representing data using fewer bits, reducing the space needed to store it.