SACE Stage 2 Digital Technologies flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Decomposition

Breaking a large problem into smaller sub-problems that can each be designed, solved and tested separately, making complex tasks manageable.

Abstraction

Removing details that are irrelevant to the problem being solved so only the essential features remain, simplifying design and reasoning.

Algorithm

A finite, ordered and unambiguous set of steps that solves a problem or completes a task, always terminating with a defined result.

Iteration

A control structure that repeats a block of steps while a condition holds or for a set number of times, avoiding duplicated code.

Trace table

A table recording each variable's value after every step of an algorithm, used to check logic and find errors before coding.

Binary search

A search of sorted data that repeatedly halves the remaining range, running in O(log n) time but requiring the data to be sorted.

Big-O notation

A notation describing how an algorithm's time or space requirements grow as input size increases, ignoring constant factors.

Flowchart decision symbol

A diamond shape in a flowchart representing a yes/no condition that determines which path execution follows next.

Functional requirement

A statement describing what a system must do, such as a specific calculation, report or user action it must support.

Non-functional requirement

A statement describing a quality the system must have, such as performance, security, usability or maintainability, rather than a behaviour.

Waterfall model

A sequential development approach where each phase completes before the next begins and requirements are fixed early, limiting later change.

Agile development

An iterative approach using short cycles and continuous stakeholder feedback, allowing requirements and designs to change between iterations.

Validation

Checking that input data satisfies predefined rules such as range, type, length or presence before the system accepts and processes it.

Verification

Confirming that data was entered or transferred accurately and matches its source, for example by double entry or checksums.

Boundary test data

Test values exactly at the edge of an accepted range, such as the minimum and maximum allowed, where errors most often occur.

Black-box testing

Testing a system's outputs against given inputs without knowledge of internal code, based only on documented requirements.

Data dictionary

A document defining each data field's name, type, size, format, validation rules and default value for a system.

Version control

A system that records changes to files over time, enabling rollback to earlier versions and merging of parallel work.

Data versus information

Data are raw unprocessed symbols, while information is data organised and interpreted in context so it supports decisions.

Primary key

A field or combination of fields that uniquely identifies each record in a table and cannot contain duplicate or null values.

Foreign key

A field in one table that references the primary key of another table, creating a relationship and enforcing referential integrity.

Third normal form

A table design where repeating groups and partial and transitive dependencies are removed, so non-key fields depend only on the primary key.

SQL SELECT

The statement that retrieves rows and columns from a table, optionally filtered by WHERE and ordered by ORDER BY.

Referential integrity

A database rule ensuring every foreign key value matches an existing primary key value, preventing orphaned records.

Quantitative data

Numeric data that can be measured, counted and analysed statistically, such as heights, prices or test scores.

Qualitative data

Non-numeric descriptive data such as interview responses or observations, analysed by identifying themes rather than statistics.

Fetch-decode-execute cycle

The repeating CPU process of retrieving an instruction from memory, interpreting it, carrying it out and storing any result.

RAM

Volatile primary memory holding programs and data currently in use; its contents are lost when power is removed.

Von Neumann architecture

A computer design where program instructions and data share the same memory and travel over a single bus to the CPU.

TCP versus UDP

TCP establishes a connection and guarantees ordered, reliable delivery; UDP sends packets without confirmation, trading reliability for speed.

DNS

The domain name system translates human-readable domain names into IP addresses so devices can locate each other on a network.

Hashing

A one-way function converting data into a fixed-length value used to verify integrity and store passwords without keeping the original.