AQA GCSE Computer Science key terms

The result that an algorithm or program should produce for a particular test, based on its requirements.

A value, or a combination of values, variables and operators, that can be evaluated to produce a result.

A penetration test in which the tester starts without any login details for the target system, to imitate an attack from outside.

The repeating process in which the CPU retrieves an instruction from memory, interprets it and carries it out.

The repeated process in which the CPU fetches an instruction from main memory, decodes it and executes it.

A network cable that carries data as pulses of light.

A named column in a database table that holds one category of data, such as a user's age.

A descriptive label identifying what a field contains, such as FirstName or TestScore.

The organisation and handling of stored files and folders, including saving, finding, renaming and deleting them.

The amount of data stored in a file, measured in units such as bits or bytes.

Hardware or software that checks incoming and outgoing network traffic against rules and blocks traffic that is not permitted.

A diagram that represents an algorithm using symbols joined by arrows to show the flow of control.

A field that refers to a primary key in another table, linking records between the tables.

The number of times a particular character or other data element occurs in a piece of data.

Two values describing a run: the number of consecutive occurrences, followed by the data value that repeats.

A subroutine that returns a value to the code that called it.

A unit of data equal to 1,000 megabytes or 1,000,000,000 bytes, written GB. The prefix giga means $10^9$.

A unit of frequency equal to one billion cycles per second: $1\text{ GHz} = 10^9\text{ Hz}$.

A variable that can be accessed throughout a program, rather than only within one subroutine.

Gaining unauthorised access to a computer system.

A magnetic secondary storage device that stores data on rotating disks and uses moving read/write heads to access it.

A magnetic secondary storage device that stores data on spinning disks.

The physical and electronic components of a computer system.

The base-16 number system, using digits 0–9 and letters A–F. A–F represent decimal values 10–15.

A programming language that expresses operations using statements rather than processor-specific machine instructions.

A device that sends or receives data over a network.

Hypertext Transfer Protocol: a protocol used to exchange web pages and other web resources between clients and servers.