Edexcel GCSE Computer Science key terms

A named sequence of instructions that performs a particular task and can be called from elsewhere in a program.

A consecutive sequence of characters taken from a larger string.

A network device that forwards received data to its intended recipient.

The rules governing how instructions must be written in a programming language.

A mistake that breaks the grammatical rules of a programming language and prevents the affected code from being executed.

Transmission Control Protocol and Internet Protocol: protocols that work together to provide reliable data transfer, addressing and routing between devices.

A model that divides network communication into four layers: application, transport, internet and link.

A unit of data equal to 1024 GiB, or $2^{40}$ bytes. Its symbol is TiB.

A weakness in software or a digital system that an attacker can exploit.

A component at the end of a bus cable that absorbs signals, preventing them from reflecting back along the cable.

Inputs chosen to check a program's behaviour against expected results.

A record of planned tests, including their purpose, inputs and expected results, with space to record actual results and whether each test passed.

A short period of processor time allocated to a process.

A record of variable values and other relevant results as a program's instructions are followed in execution order.

A distinctive sign, such as a name or logo, that identifies one business’s goods or services and distinguishes them from those of other businesses.

A program that converts source code into machine code so that a processor can execute it.

The amount of data transferred across a network per second, measured in bits per second.

Malware disguised as legitimate software, which tricks a user into installing or running it.

A table showing every possible combination of input values and the corresponding output of a Boolean expression.

A data structure containing one-dimensional structures, with two indices needed to access an individual item within them.

A binary representation of signed integers in which the leftmost bit has a negative place value. In eight bits, the column values are −128, 64, 32, 16, 8, 4, 2 and 1.

A signed binary representation in which the most significant bit has a negative place value. In 8-bit two’s complement, this value is −128 and the range is −128 to +127.

Changing a value from one data type to another, such as converting the string "12" to the integer 12.

A binary representation of a non-negative whole number in which no bit is used to indicate a negative sign.

A whole number represented without a negative sign. An 8-bit unsigned integer can have a value from 0 to 255.

A subprogram written by the programmer to carry out a task needed by their program.

An identifier, such as a username, that tells a system which user account someone claims to own.