England · AQASyllabus
Computer Science syllabus, dot point by dot point
Every dot point in the England 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.
4.8 Communication and networking
Module overview →- How do the client-server and peer-to-peer models work, and how does the web fit in?Understand the client-server and peer-to-peer models, web technologies including HTML, CSS and JavaScript, the role of web servers, and the use of APIs and thin versus thick clients.8 min answer →
- How is data physically transmitted between devices?Understand serial and parallel transmission, synchronous and asynchronous transmission, bit rate, baud rate and bandwidth, and the trade-offs between these methods.8 min answer →
- How are networks kept secure and how does encryption protect data?Understand network security threats, firewalls and proxy servers, the use of encryption, digital certificates and digital signatures, and the difference between symmetric and asymmetric encryption in transmission.9 min answer →
- What are the main network types, topologies and the role of network hardware?Understand LANs and WANs, star and bus topologies, wired and wireless networks, the role of switches, routers and the Wi-Fi standards including CSMA/CA and SSID.9 min answer →
- How does the internet work, and what is the TCP/IP protocol stack?Understand the structure of the internet, packet switching, the TCP/IP four-layer model, IP addressing, DNS, routers and gateways, and how data is routed across networks.9 min answer →
4.7 Computer organisation and architecture
Module overview →- What is machine code structure and how do addressing modes find operands?Understand the structure of a machine code instruction (opcode and operand), immediate and direct addressing modes, and the relationship between assembly language and machine code.7 min answer →
- What are the main internal components of a computer and how are they connected?Understand the internal components of a computer, the role of the processor, main memory and buses, and the difference between RAM, ROM and cache memory.8 min answer →
- What are the processor's components, and how does the fetch-execute cycle work?Understand the components of the processor (ALU, control unit, registers), the fetch-decode-execute cycle, the role of each register, and the factors affecting processor performance.9 min answer →
- How does secondary storage work and how do the main types compare?Understand the need for secondary storage and the principles, advantages and disadvantages of magnetic, optical and solid state storage.8 min answer →
- What is the stored program concept and how do the main CPU architectures differ?Understand the stored program concept, the Von Neumann architecture, the Harvard architecture, and the differences between them.7 min answer →
4.6 Fundamentals of computer systems
Module overview →- How are programming languages classified and what are the main paradigms?Understand the classification of programming languages by level (low and high) and by paradigm (imperative, object-oriented, declarative and functional), and the use of machine code and assembly language.8 min answer →
- What is the difference between hardware and software, and what does an operating system do?Understand the relationship between hardware and software, the classification of software into system and application software, and the role of the operating system and utility programs.8 min answer →
- How do logic gates and Boolean algebra build a computer's logic?Understand the logic gates NOT, AND, OR, XOR, NAND and NOR, their truth tables, combining gates into logic circuits, and simplifying expressions using Boolean algebra.9 min answer →
- How is source code translated to run, and what does a compiler actually do?Understand assemblers, compilers and interpreters, the differences between them, the stages of compilation (lexical analysis, syntax analysis, code generation and optimisation), and intermediate code.9 min answer →
4.13 Fundamentals of functional programming
Module overview →- What is functional programming and how does it differ from imperative programming?Understand the functional programming paradigm, functions as first-class objects, function application, partial application and composition, and the higher-order functions map, filter and reduce.9 min answer →
- What are the moral, ethical, legal and cultural consequences of computing?Understand the moral, ethical, legal and cultural issues raised by computing, the relevant UK legislation, privacy and data protection, and the responsibilities of computer professionals.8 min answer →
4.5 Fundamentals of data representation
Module overview →- How are signed integers, fractions and binary arithmetic represented?Understand unsigned and signed binary using two's complement, binary addition and subtraction, fixed point and floating point representation of real numbers, and the effects of overflow and rounding.9 min answer →
- What are bits and bytes, and how are storage capacities measured?Understand the bit and byte, the units of information capacity, binary and decimal prefixes (kibi versus kilo), and how the number of bits limits the range of values that can be represented.7 min answer →
- How are characters represented as binary using ASCII and Unicode?Understand character encoding using ASCII and Unicode, the limitations of ASCII, why Unicode was introduced, and the relationship between a character set and a character code.7 min answer →
- How is data compressed, encrypted and checked for errors?Understand lossy and lossless compression, run length encoding and dictionary-based compression, symmetric and asymmetric encryption, and error-checking methods such as parity and check digits.9 min answer →
- What number bases do computers use and how do we convert between them?Understand the decimal, binary and hexadecimal number systems, why computers use binary and hexadecimal, and how to convert between the three bases.8 min answer →
- How are images and sound represented digitally?Understand how bitmap images are represented using pixels, colour depth and resolution, how analogue sound is sampled, and the effect of sample rate, resolution and metadata on quality and file size.9 min answer →
4.9 Fundamentals of databases
Module overview →- How do we model the data and relationships in a real-world system?Understand conceptual data modelling, entities, attributes and relationships, entity relationship (ER) diagrams, and the degrees of relationship (one-to-one, one-to-many, many-to-many).8 min answer →
- What is a relational database and why do we normalise to third normal form?Understand relational databases, primary and foreign keys, the problems of data redundancy, and normalisation to first, second and third normal form.9 min answer →
- How do we query and modify a relational database using SQL?Understand SQL for retrieving data with SELECT, FROM, WHERE and ORDER BY, joining tables, and modifying data with INSERT, UPDATE and DELETE.9 min answer →
- How do databases keep data consistent and safe during concurrent transactions?Understand transaction processing, the ACID properties, record locking and the deadlock that can result, redundancy and database recovery.8 min answer →
4.3 Fundamentals of algorithms
Module overview →- How do we measure and compare the efficiency of algorithms?Understand Big-O notation for time and space complexity, the common orders of growth, how to determine the complexity of an algorithm, and the meaning of best, average and worst case.8 min answer →
- How does Dijkstra's algorithm find the shortest path in a weighted graph?Understand Dijkstra's shortest path algorithm, how it finds the lowest-cost path from a start vertex, the role of a priority queue, and its applications.8 min answer →
- How are graphs and trees systematically traversed?Understand depth-first and breadth-first graph traversal, the data structures they use, and the pre-order, in-order and post-order tree traversal algorithms.8 min answer →
- How do linear and binary search work, and which is faster?Understand the linear search and binary search algorithms, how each works, their requirements, and their time complexity.8 min answer →
- How do bubble sort and merge sort work, and which is more efficient?Understand the bubble sort and merge sort algorithms, how each orders a list, their time complexity, and the trade-off between them.8 min answer →
4.2 Fundamentals of data structures
Module overview →- How are arrays, records and fields used to store structured data?Understand arrays (one, two and three dimensional), records and fields, and the difference between static and dynamic data structures.8 min answer →
- What is a dictionary and how does it relate to a hash table?Understand a dictionary as an abstract data type of key-value pairs, its operations, how it is typically implemented using a hash table, and when a dictionary is appropriate.7 min answer →
- What is a graph and how is it represented in a computer?Understand graphs, vertices and edges, directed, undirected and weighted graphs, and how a graph is represented as an adjacency matrix or an adjacency list.8 min answer →
- How does a hash table give near-instant lookup, and how are collisions handled?Understand a hash table, the role of a hashing algorithm, how a key maps to an index, the meaning of a collision, and collision-resolution methods such as rehashing and chaining.8 min answer →
- How does a queue work and where is it used?Understand the queue abstract data type, FIFO behaviour, linear, circular and priority queues, and the enqueue and dequeue operations using front and rear pointers.8 min answer →
- How does a stack work and why is it used for calls and recursion?Understand the stack abstract data type, LIFO behaviour, the push, pop and peek operations using a stack pointer, and the use of stacks for subroutine calls and recursion.8 min answer →
- What is a tree and how is a binary search tree used?Understand trees as a connected, undirected graph with no cycles, the terms root, child, parent, leaf and subtree, and the structure and use of a binary search tree.8 min answer →
4.1 Fundamentals of programming
Module overview →- How do programs perform arithmetic, comparison and logical operations on data?Use arithmetic operations including integer division, modulus and exponentiation, relational operators, and the Boolean operators AND, OR and NOT, and understand operator precedence.8 min answer →
- What are the built-in data types and how is data stored in memory?Understand the built-in data types: integer, real or float, Boolean, character and string, and understand records, arrays and user-defined data types built from them.8 min answer →
- What are the core ideas of object-oriented programming?Understand classes and objects, attributes and methods, instantiation, encapsulation, inheritance and polymorphism, and the principle of object-oriented design.9 min answer →
- What are the core programming constructs every imperative program is built from?Understand and use the three basic programming constructs (sequence, selection and iteration), definite and indefinite iteration, nested constructs, and the meaning of constants and variables.8 min answer →
- How do subroutines, parameters and scope let us structure and reuse code?Understand and use subroutines (procedures and functions), parameters, return values, local and global variables, scope, and the use of an interface and recursion.9 min answer →
4.4 Theory of computation
Module overview →- What are abstraction and automation, and how do we solve problems computationally?Understand abstraction, the different forms of abstraction, decomposition, automation, and the components of computational thinking used to solve problems.8 min answer →
- How are problems and algorithms classified by how hard they are to solve?Understand tractable and intractable problems, the classes P and NP, the idea of computable and non-computable problems, and the use of heuristics for intractable problems.8 min answer →
- What is a finite state machine and how is it represented?Understand finite state machines with and without output, state transition diagrams and tables, and the use of an FSM to recognise inputs or model behaviour.8 min answer →
- What are regular expressions, and how do regular and context-free languages differ?Understand regular expressions and regular languages, the link between regular expressions and finite state machines, the limits of regular languages, and context-free languages described by a BNF grammar.9 min answer →
- What is a Turing machine and why does it matter for the theory of computation?Understand the Turing machine model, its components, the idea of a universal Turing machine, and the link to the limits of computation and the halting problem.8 min answer →