Computer Science key terms

The ability of different hardware and software systems to exchange data and work together.

Software that translates and executes source code one statement at a time, interpreting the source again whenever the program is run.

Data of the correct data type which should be rejected by a computer system.

A numerical address used to identify a device on an IP network and direct communications to it.

Internet Protocol version 4, which uses 32-bit addresses normally written as four denary numbers separated by full stops.

Internet Protocol version 6, which uses 128-bit addresses. A full address is written as eight groups of four hexadecimal digits separated by colons.

The repetition of a group of instructions in an algorithm.

Repeated testing of modules during program development, using the results to correct and improve the code.

An identifier used to access an associated value in a dictionary.

A unit of data equal to 1,000 bytes using the decimal convention.

A Local Area Network: a network covering a relatively small geographical area, such as a home, school or office, usually owned and managed by one person or organisation.

A division of network functionality that handles a specific part of the communication task.

A zero placed before the first non-zero digit of a number. Leading zeros do not change the value of a positive binary integer.

The principle of giving a user only the permissions needed for their role.

The rightmost bit in a binary representation, occupying the position with the smallest place value. For a binary integer, its place value is 1.

A question about how the law applies, whether an action is lawful or who has legal responsibility.

A check that input contains an acceptable number of characters.

A searching algorithm that checks items one at a time from the beginning until a match is found or all items have been checked. The data need not be sorted.

A network connecting devices over a relatively small geographical area, such as a home, school or office.

A variable declared inside a subprogram and accessible only within that subprogram.

A binary shift that fills newly empty positions with zeros and discards bits moved beyond the available width.

A diagram showing how logic gates are connected to turn Boolean inputs into an output.

A mistake in a program’s instructions that causes incorrect behaviour, even though the code obeys the language’s grammatical rules.

A component that applies a Boolean operation to its input or inputs to produce an output.

The statements belonging to a loop, executed during each repetition.

A method of reducing file size without losing information, allowing the exact original data to be recovered.

A method of reducing file size by permanently removing some of the original data. The exact original data cannot be recovered from the compressed file.

A programming language closely related to a processor’s instructions and hardware, giving more direct control but being harder for humans to read and write.

A Media Access Control address assigned to a network interface, used to identify it when delivering data within a local network.

Binary instructions that a processor can execute directly. The instructions are specific to a particular processor type.