← Computer Science syllabus

WalesComputer Science

Unit 3 Programming and System Development

7 dot points across 7 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How is data kept secure, accurate and recoverable in a software system, and how do backup, validation and encryption protect it?

Describe data security and integrity measures: backup and recovery, validation and verification, error detection, and encryption in depth.
A focused answer to WJEC A-Level Computer Science Unit 3 data security and integrity, covering backup and recovery, validation and verification, error detection methods such as parity and checksums, and encryption in depth.
12 min answer →

How are advanced data structures built and traversed, and how do recursion and advanced algorithms operate on them?

Describe and apply advanced data structures and algorithms: linked lists, trees and their traversals, recursion, and advanced searching and sorting.
A focused answer to WJEC A-Level Computer Science Unit 3 data structures and algorithms, covering linked lists and pointers, binary tree traversals, recursion, and advanced searching and sorting with efficiency.
13 min answer →

How is data transmitted reliably across networks, and how do protocols, layers and network security work in depth?

Describe data transmission methods, packet switching, the layered protocol model, network hardware, and network security in depth.
A focused answer to WJEC A-Level Computer Science Unit 3 data transmission and networks, covering serial and parallel transmission, packet switching, the layered protocol model, network hardware, and network security.
13 min answer →

What are the main programming paradigms, and how does object-oriented programming use classes, objects and inheritance?

Explain the procedural, object-oriented and declarative paradigms, and describe classes, objects, encapsulation, inheritance and polymorphism.
A focused answer to WJEC A-Level Computer Science Unit 3 programming paradigms, covering procedural, object-oriented and declarative programming, and the OOP concepts of classes, objects, encapsulation, inheritance and polymorphism.
13 min answer →

How are complex Boolean expressions simplified with Karnaugh maps, and how do programming constructs build a working program?

Simplify Boolean expressions using Boolean algebra and Karnaugh maps, and use programming constructs to construct programs.
A focused answer to WJEC A-Level Computer Science Unit 3 programs and logical operations, covering Boolean simplification, Karnaugh maps, sum-of-products form, and building programs from constructs and subroutines.
13 min answer →

How is a system designed, tested, installed and maintained so that it is reliable and meets its requirements?

Describe system design, testing strategies, methods of installation and changeover, documentation, evaluation and maintenance.
A focused answer to WJEC A-Level Computer Science Unit 3 system design and testing, covering design specification, testing strategies, methods of system changeover, documentation, evaluation and the types of maintenance.
13 min answer →

How is a software system developed from a problem to a solution, and what stages and methodologies guide the process?

Describe the systems development life cycle, its stages, and development methodologies including the waterfall and agile approaches.
A focused answer to WJEC A-Level Computer Science Unit 3 systems analysis, covering the stages of the systems development life cycle, feasibility and requirements, and the waterfall and agile methodologies.
13 min answer →