Edexcel GCSE Computer Science key terms

A base-10 number system using the digits 0–9.

Software that enables a computer system to communicate with and control a particular hardware device.

The stages a digital device passes through, from extracting its raw materials and manufacturing it to use and eventual disposal.

A representation using separate numerical values rather than a continuously varying signal.

Reorganising file blocks on a magnetic hard drive so that related blocks are stored contiguously, meaning next to one another.

Following an algorithm manually, instruction by instruction, without executing it on a computer.

How economically a program uses resources to complete its task, assessed through measures such as comparisons, loop passes and memory use.

An individual item in a data structure.

A computer system built into a larger device to perform a dedicated function.

Representing data using an agreed system of codes, such as converting text characters into binary codes.

The process of encoding readable data so that it cannot be understood without the appropriate decryption key.

The amount of energy used by an activity or system, such as manufacturing a computer or running a server.

Input that does not meet the program's input rules, such as an out-of-range value or an incorrect data type.

Information produced by a programming environment to describe an error and help locate it.

A family of protocols for transferring data over a wired local area network.

Testing a computer system's security with the owner's permission to identify weaknesses and help get them fixed.

A question about whether an action is right, wrong or fair, considering its effects on people.

Discarded electrical or electronic equipment, such as unwanted computers, phones and monitors.

A compiled program that can be run without translating its source code again.

Raising a number to a power, written ** in Python. For example, 3 ** 2 calculates $3^2 = 9$.

A combination of values, variables and operators that a program evaluates to produce a value.

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

One item of data within a record, such as a student's name.

The organisation, storage and retrieval of files by an operating system.

A setting that determines whether a user or group may perform an action on a file, such as reading, writing, deleting or executing it.

The process of repairing a damaged file or extracting as much usable data from it as possible.

Hardware or software that monitors incoming and outgoing network traffic and applies rules to decide which traffic to allow or block.