NCEA Level 2 Digital Technologies key terms

A finite, ordered set of unambiguous steps that solves a problem or completes a task, such as sorting a list or finding the largest value in a data set.

A named storage location in a program whose value can change while the program runs. Its name lets code read and update data without tracking memory addresses directly.

The category that defines what kind of values a variable may hold and which operations apply, for example integer, float, boolean, string, or a structured type such as a list.

A control structure that chooses which statements run based on a condition being true or false, implemented with if, else-if, and else statements or an equivalent construct.

A control structure that repeats a block of statements, either a fixed number of times or while a condition holds, using loops such as for and while.

A named, reusable block of code that performs one task, may accept parameters, and may return a value to the code that called it.

A named input declared by a function that receives a value when the function is called, letting the same code work with different data each time.

A data type with exactly two possible values, true or false, used to represent conditions and to control selection and iteration in a program.

The process of finding, diagnosing, and fixing errors in a program by reading code, tracing values, adding test output, and re-running tests until behaviour is correct.

A mistake that breaks the grammar rules of a programming language, such as a missing bracket or misspelled keyword, which usually stops the program from compiling or running at all.

A structured, language-independent description of an algorithm written in plain statements, used to plan and communicate logic before it is translated into real code.

Designing software as separate, self-contained parts such as functions or modules, so each part can be built, tested, and changed with limited effect on the rest.

The region of a program in which a variable or function name is accessible; local scope limits access to one block or function, while global scope makes it visible more widely.

A single integrated circuit containing a processor, memory, and input/output peripherals, programmed to control a device such as a robot, appliance, or sensor node.

General-purpose input/output: configurable pins on a microcontroller or single-board computer that software can set high or low, or read as a digital input.

A component that converts a physical quantity such as temperature, light, distance, or motion into an electrical signal that a microcontroller can read and process.

An output device that converts an electrical control signal into physical action, for example a motor, servo, relay, buzzer, or LED, allowing a system to affect its environment.

A signal that varies continuously over a range of values, such as a voltage from a temperature sensor, which must be converted to numbers before a digital processor can use it.

Analog-to-digital converter: a circuit that samples a continuously varying voltage and outputs a discrete numeric value, often with a resolution measured in bits.

A technique that switches a digital output on and off rapidly and varies the proportion of on-time, giving an average effect such as dimmed LED brightness or motor speed.

A resistor connected between a digital input pin and the supply voltage so the pin reads a stable high when nothing pulls it low, preventing floating, unreliable readings.

A computer built into a larger device to perform a dedicated control function, typically with limited memory and power, running fixed firmware rather than general-purpose applications.

Software stored on a device's non-volatile memory that controls its hardware directly and is rarely changed by the user, sitting between the hardware and any higher-level software.

A collection of data organised into tables of rows and columns, with relationships between tables expressed through shared key values rather than nested structures.

A column or combination of columns whose value uniquely identifies each row in a table, so no two rows share the same key and no key value is null.

A column in one table that holds a primary key value from another table, creating a link between the two tables and enforcing that referenced records exist.

Structured Query Language: the standard language for defining, querying, and modifying data in a relational database, including statements such as SELECT, INSERT, UPDATE, and DELETE.

A request for data from a database that specifies which tables, fields, filters, and sort order are wanted, returning a result set rather than changing stored data.

Rules applied when data is entered to check it is acceptable, such as a required field, a range check, or a list of allowed values, reducing incorrect data in a system.

Checking that data was copied or transferred accurately, for example by entering a value twice or using a checksum, to catch errors introduced during input or transmission.

Transforming readable data into an unreadable form using a key, so only someone holding the correct key can reverse the process and read the original content.

The process of proving a user's or system's claimed identity, typically with something they know, possess, or are, before granting access to protected data or services.

The amount of detail an image, screen, or sampled signal can represent, measured in pixels for displays or bits for converters; higher resolution captures finer detail but uses more storage.

The smallest individually controllable element of a raster image or display, holding colour information; many pixels together form the visible picture.

The number of bits used to store the colour of each pixel, determining how many distinct colours are possible, such as 8-bit, 16-bit, or 24-bit colour.

Reducing file size by permanently discarding some data that is least noticeable to human perception, as in JPEG images or MP3 audio, so quality drops slightly with each save.

Reducing file size by encoding data more efficiently so the original can be rebuilt exactly, as with PNG images or ZIP archives, with no loss of quality.

An image described by mathematical shapes, paths, and fills rather than a grid of pixels, so it can be scaled to any size without becoming pixelated.