NCEA L1 Digital Tech key terms

A finite, ordered set of steps that turns an input into a desired output. It must be unambiguous so that anyone following it gets the same result.

A named storage location in a program whose value can change while the program runs. Each variable has a type and a current value held in memory.

A named value fixed when the program is written and not changed during execution. Constants make code readable and prevent accidental edits to important values.

A classification of values that determines what can be stored and which operations are allowed, such as integer, float, string or Boolean.

The statement that stores a value into a variable, often written with an equals sign. The right-hand side is evaluated first, then placed into the named location.

A data type holding a sequence of characters, such as text or a name. Strings can be joined, compared and searched character by character.

A data type with only two possible values, true or false. Boolean expressions are used to control decisions and loops in programs.

Repeating a block of instructions, either a set number of times or while a condition remains true. Iteration avoids duplicating the same code many times.

A programming structure that repeats instructions. Counted loops run a known number of times; conditional loops continue until a test becomes false.

A structure that chooses between alternative paths using a condition, such as if, else-if and else. Only the branch whose condition is true executes.

A symbol that compares two values and returns true or false, for example equals, not equal, greater than, less than, and greater than or equal.

A named block of code that performs a task and can be called repeatedly, optionally taking parameters and returning a value. Functions make programs easier to reuse and test.

A named value a function or procedure expects when it is called, letting the same code work with different inputs. Arguments are the actual values supplied at the call.

The result a function sends back to the code that called it. A function without a return value performs an action but passes nothing back.

Finding and fixing errors in a program. It involves reproducing the fault, locating its cause using traces or print statements, then correcting and retesting the code.

A mistake that breaks the grammar rules of a programming language, such as a missing bracket or misspelled keyword. The program will not run until it is fixed.

A program that runs without crashing but produces the wrong result because the reasoning or order of steps is wrong. Testing with known inputs helps reveal it.

A specific input with the expected output, used to check that a program behaves correctly. Good sets include normal, boundary and invalid values.

A structured, plain-language way of describing an algorithm without the strict rules of a real programming language. It focuses on logic and can be translated into code later.

A diagram of an algorithm using standard shapes: ovals for start and end, parallelograms for input and output, rectangles for processes and diamonds for decisions.

Joining two or more strings end to end to form a new string, for example combining a first name and a last name with a space between them.

Hardware that sends data or commands into a computer system, such as a keyboard, mouse, microphone, sensor or button. It converts a physical action into a signal the system can process.

Hardware that presents or acts on the results produced by a system, such as a screen, speaker, motor, LED or buzzer. It turns electrical signals into something a user or machine can use.

A small self-contained computer on a single chip containing a processor, memory and input/output pins. It runs one stored program repeatedly to control a device.

General-purpose input/output: programmable pins on a microcontroller that can be set as inputs to read signals or as outputs to drive components. Each pin usually works at logic voltage levels.

A component that measures a physical quantity such as temperature, light or distance and converts it into an electrical signal a system can read.

A component that converts an electrical control signal into physical movement or action, for example a motor, servo, relay or solenoid.

A signal that varies continuously over a range of values, like the voltage from a light-dependent resistor. Real-world measurements are usually analogue before conversion.

A signal that takes only discrete levels, typically high or low representing 1 and 0. Digital signals are less affected by noise than continuous analogue voltages.

Analogue-to-digital converter: a circuit that samples a continuous voltage and outputs a number representing its level. Resolution in bits sets how finely the range is divided.

A computer built into a device to perform a dedicated control task, often with limited memory and no general-purpose interface. Examples include washing machines, drones and traffic lights.

Software stored permanently on a device's memory chip that controls its basic hardware behaviour. It usually starts automatically and is rarely changed by the user.

The physical parts of a computer system that can be touched, such as the processor, memory, circuit board, cables and case. Hardware executes the instructions software provides.

The programs, applications and instructions that tell hardware what to do. Software is stored as files and loaded into memory to run.

System software that manages hardware, memory, files and running programs, and provides a user interface. It lets applications use resources without controlling hardware directly.

A device connected to a computer to add capability, such as a printer, webcam, scanner or external drive. Peripherals may be internal or external and need a connection standard.

Organising stored data into folders and files with meaningful names, so information can be found, backed up and shared reliably. Good practice includes clear naming and version control.

A copy of data kept separately from the original so it can be restored after loss, damage or attack. Effective backups are regular, verified and stored off the main device.

Software written to harm or exploit a system, including viruses, worms, ransomware and spyware. It often spreads through downloads, attachments or unpatched weaknesses.

Scrambling data using a key so that only someone with the correct key can read it. It protects information in transit and at rest if the key stays secret.

Checking that a user or device is who they claim to be, usually with a password, token or biometric. It is different from authorisation, which decides what they may access.

How easily and effectively people can use a system to achieve their goals, covering learnability, efficiency, error prevention and satisfaction. It is assessed by observing real users.

Designing digital products so people with disabilities or different needs can use them, for example with captions, keyboard navigation, readable contrast and alternative text.

The smallest addressable unit of a digital image, holding a colour value. Image resolution is often described by the number of pixels across and down.

The amount of detail an image or display can hold, usually given as width by height in pixels. Higher resolution allows more detail but increases file size.

An image stored as a grid of pixels, suited to photographs but showing jagged edges when enlarged. Common formats include JPEG, PNG and GIF.

An image stored as mathematical shapes, lines and curves, so it scales without losing quality. It suits logos, icons and diagrams but not detailed photographs.

The number of bits used to store the colour of each pixel, which sets how many distinct colours are possible. More bits give smoother colour but larger files.

Reducing file size by removing redundancy or discarding detail. Lossless compression restores the original exactly; lossy compression permanently removes some data.

The parts of a system a person sees and interacts with, including menus, buttons, layouts and feedback. A clear interface reduces errors and helps users complete tasks quickly.