Wales Β· WJECSyllabus
Computer Science syllabus, dot point by dot point
Every dot point in the Wales Computer Sciencesyllabus, with a focused answer for each one. Click any dot point for a worked explainer, past exam questions, and links to related dot points. Written by Claude Opus 4.8, Anthropic's latest AI.
Unit 1: Algorithms and programming principles
Module overview β- What is computational thinking, and how are algorithms expressed using flowcharts and pseudocode?Computational thinking through decomposition and abstraction, what an algorithm is, and expressing algorithms using flowcharts and pseudocode.9 min answer β
- What are the logic operators AND, OR and NOT, how do truth tables work, and what do logic gates do?Boolean logic using the AND, OR and NOT operators, constructing truth tables, the logic gates, and simplifying simple logic expressions.8 min answer β
- What are the three basic programming constructs, and how are variables, constants and operators used?The three programming constructs (sequence, selection and iteration), the use of variables and constants, and arithmetic, relational and logical operators.9 min answer β
- How do the linear search and binary search algorithms work, and when is each suitable?The linear search and binary search algorithms, how each works, and the conditions under which each is suitable.9 min answer β
- How do the bubble sort and merge sort algorithms put data into order, and how do they compare?The bubble sort and merge sort algorithms, how each puts data into order, and the relative efficiency of the two methods.9 min answer β
- What are subprograms, and why is a modular, structured approach to programming used?The use of subprograms (procedures and functions) and parameters, and the benefits of a modular, structured approach to programming.8 min answer β
Unit 1: Communication and networks
Module overview β- What are IP and MAC addresses, what does DNS do, and how is data routed across the internet?IP addresses and MAC addresses, the purpose of the Domain Name System (DNS), and how data is routed across the internet.8 min answer β
- What hardware connects a network, and how is data transmitted across it?The hardware needed for networking (network interface card, switch, router, transmission media), wired versus wireless connections, bandwidth, and how data is sent in packets.9 min answer β
- What is a computer network, and how do LANs, WANs, client-server and peer-to-peer models and topologies differ?The purpose of computer networks, the difference between LANs and WANs, client-server and peer-to-peer models, and common network topologies.9 min answer β
- What are network protocols, what are the common ones, and why are protocols arranged in layers?The purpose of protocols, common protocols (TCP/IP, HTTP and HTTPS, FTP, SMTP), and why network communication is organised into layers.8 min answer β
Unit 1: Hardware and communication
Module overview β- What are input and output devices, and how do you choose suitable devices for a task?The purpose of input and output devices, examples of each, and choosing appropriate input and output devices for a given situation.8 min answer β
- What is the difference between RAM and ROM, and what is virtual memory used for?The purpose and characteristics of RAM and ROM, the difference between volatile and non-volatile memory, and the purpose of virtual memory.8 min answer β
- What factors affect how fast a processor performs, and how do clock speed, cores and cache change performance?The factors affecting processor performance: clock speed, the number of cores, and the amount and use of cache memory.8 min answer β
- Why is secondary storage needed, and how do magnetic, optical and solid-state storage compare?The need for secondary storage, the characteristics of magnetic, optical and solid-state storage, and calculating storage requirements and capacity.8 min answer β
- What is the CPU made of, and what is the von Neumann stored-program architecture?The purpose and main components of the CPU (the ALU, the control unit and registers) and the von Neumann stored-program architecture.8 min answer β
- What happens during the fetch-decode-execute cycle, and what is the role of each register?The fetch-decode-execute cycle and the roles of the registers used in it (the program counter, memory address register, memory data register and accumulator).8 min answer β
Unit 1: Security and data management
Module overview β- What are the main cyber security threats to computer systems and networks?Common cyber security threats, including malware, phishing, social engineering, brute-force attacks, denial-of-service attacks, SQL injection and data interception.9 min answer β
- How can computer systems and networks be protected from cyber security threats?Methods of protecting systems and networks, including firewalls, encryption, authentication, anti-malware, penetration testing, network policies and managing cookies.9 min answer β
Unit 1: Organisation and structure of data
Module overview β- How is the security and integrity of data protected through backups, archiving and integrity processes?Data security and integrity processes, including backups, archiving, and methods of keeping data accurate and consistent.8 min answer β
- What are the common data types and data structures, and how are validation and verification used to keep data correct?The common data types, the use of data structures such as arrays and records, and the difference between validation and verification.8 min answer β
- How are databases organised, and what is the difference between a flat file and a relational database?The purpose of a database, the terms table, record, field and key, the difference between flat-file and relational databases, and the idea of a distributed system.9 min answer β
Unit 1: Data representation and data types
Module overview β- Why do computers use the binary number system, and how do you convert between binary and denary?The binary and denary number systems, why computers store data in binary, the units of data capacity, and converting whole numbers between binary and denary.8 min answer β
- How do you add binary numbers, what is overflow, and how does an arithmetic shift multiply or divide a binary number?Adding two binary numbers using the carry rules, the meaning of overflow, and using arithmetic (binary) shifts to multiply and divide by powers of two.8 min answer β
- How are text characters stored in a computer using character sets such as ASCII and Unicode?Representing characters in binary using character sets, the ASCII and Unicode character sets, and the relationship between a character, its character code and the number of bits needed.8 min answer β
- Why is data compressed, and how do lossy and lossless compression, including run-length encoding, work?The need for compression, the difference between lossy and lossless compression, and how run-length encoding compresses data.8 min answer β
- What is hexadecimal, why is it used in computing, and how do you convert between hexadecimal, binary and denary?The hexadecimal number system, why hexadecimal is used as a shorthand for binary, and converting between hexadecimal, binary and denary.8 min answer β
- How are bitmap images stored in binary, and how do resolution and colour depth affect file size?Representing bitmap images as pixels, the meaning of resolution and colour depth, calculating the file size of an image, and the role of metadata.9 min answer β
- How are negative whole numbers stored in binary using sign and magnitude and two's complement?Representing signed (negative and positive) integers in binary using the sign and magnitude method and the two's complement method, and converting between them.9 min answer β
- How is analogue sound converted into binary, and how do sample rate and bit depth affect quality and file size?Representing sound in binary by sampling an analogue wave, the meaning of sample rate and sample resolution (bit depth), and how they affect sound quality and file size.8 min answer β
Unit 1: Software and system development
Module overview β- What is the difference between low-level and high-level languages, and how do assemblers, compilers and interpreters translate programs?Low-level and high-level programming languages, the need for translators, and the differences between assemblers, compilers and interpreters.9 min answer β
- What does an operating system do, and what are its main functions?The purpose of the operating system and its main functions: managing memory, processes, peripherals and files, providing a user interface, and managing security.8 min answer β
- What is the difference between system software and application software?The need for different types of software, and the difference between system software and application software with examples of each.8 min answer β
- What is utility software, and what do common utility programs do?The purpose of utility software and the function of common utilities, including antivirus, backup, file compression and disk defragmentation.8 min answer β
Unit 1: Ethical, legal and environmental impacts
Module overview β- What are the environmental and social impacts of digital technology, including e-commerce?The environmental impacts of digital technology (energy use, e-waste and resources) and its social impacts, including the effects of e-commerce.8 min answer β
- What laws and ethical issues govern the use of computers and data?The main legislation governing computer use (data protection, the Computer Misuse Act and copyright law) and the ethical and cultural issues raised by computing.9 min answer β
- What are the stages of the software development life cycle, and how is software tested?The stages of the software development life cycle (analysis, design, development, testing, evaluation and maintenance) and the use of test plans and test data.9 min answer β
- How are the practical programming components (Unit 2 and Unit 3) assessed, and what do they require?An overview of the practical assessment: Unit 2 (the on-screen computational thinking and programming examination) and Unit 3 (the non-exam software development project).8 min answer β