England · OCRSyllabus
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.
2.1 Algorithms
Module overview →- What are abstraction, decomposition and algorithmic thinking, and how do they help you solve a problem?The principles of computational thinking: abstraction, decomposition and algorithmic thinking, and how each is used to analyse a problem and design a solution.9 min answer →
- How do you design and present an algorithm using pseudocode and flowcharts?Producing algorithms using pseudocode and flowcharts to solve a problem, identifying the inputs, processes and outputs, and interpreting, correcting and refining algorithms others have written.11 min answer →
- How do linear search and binary search work, and when is each one appropriate?Standard searching algorithms: linear search and binary search, how each works step by step, the requirement that binary search needs a sorted list, and the comparison of their efficiency.10 min answer →
- How do bubble sort, insertion sort and merge sort each put a list in order?Standard sorting algorithms: bubble sort, insertion sort and merge sort, how each works step by step, and how they compare in approach and efficiency.12 min answer →
- How do you use a trace table to work through an algorithm and find its output or its purpose?Using trace tables to determine the output of an algorithm and to follow how the values of variables change, and determining the purpose of a simple algorithm.10 min answer →
1.3 Computer networks, connections and protocols
Module overview →- How are networks physically arranged, and what hardware connects them?Star and mesh network topologies and their advantages and disadvantages, and the role of network hardware (NIC, switch, router, wireless access point and transmission media).9 min answer →
- What is a network, and what makes one perform well or badly?Types of network (LAN and WAN), the factors that affect network performance, and the difference between client-server and peer-to-peer networks.9 min answer →
- What are network protocols, and why are networks organised into layers?Common network protocols (TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP), the concept of layers and the benefits of using them.9 min answer →
- How do wired and wireless connections compare, and how is data sent over them?Wired (Ethernet) versus wireless (Wi-Fi) connections and their relative advantages and disadvantages, and the role of encryption in wireless networks.8 min answer →
1.6 Ethical, legal, cultural and environmental impacts
Module overview →- How does digital technology change society, and who gets left behind?The cultural impacts of digital technology: the digital divide, changes to work and jobs through automation, the effect of social media and the internet on behaviour and society, and issues of access and inclusion.9 min answer →
- What effect does the manufacture, use and disposal of digital technology have on the environment?The environmental impacts of digital technology: the energy used in manufacture and operation, the raw materials and rare metals consumed, electronic waste and its disposal, and ways the impact can be reduced.9 min answer →
- How do you analyse the impact of a piece of digital technology on the people and groups it affects?How to investigate and discuss computer science technologies while considering ethical, legal, cultural, environmental and privacy issues, and how to identify the stakeholders affected by a given technology.10 min answer →
- Which laws govern the use of computers and data, and what does each one cover?Legislation relevant to computer science: the Data Protection Act 2018, the Computer Misuse Act 1990, the Copyright, Designs and Patents Act 1988, and software licensing (open source versus proprietary).11 min answer →
- What privacy issues does the collection and use of personal data create?The privacy issues raised by digital technology: what personal data is, how it is collected and used by organisations and websites, the risks to individuals, and the tension between convenience, security and privacy.10 min answer →
2.5 Programming languages and IDEs
Module overview →- What are compilers, interpreters and assemblers, and how do they differ?The purpose of translators, the characteristics of a compiler and an interpreter and how they differ, and the role of an assembler in translating assembly language.10 min answer →
- What is the difference between high-level and low-level languages, and why use each?The characteristics and purpose of high-level and low-level languages, the difference between machine code and assembly language, and the advantages and disadvantages of each level.9 min answer →
- What is an IDE, and what tools does it provide to help a programmer?The common tools and facilities available in an integrated development environment (IDE): the editor, error diagnostics, run-time environment and translators, and how each helps a programmer.9 min answer →
- How do programming languages, source code, machine code and IDEs fit together in writing software?How programming languages, source code, translators and integrated development environments fit together: why source code must be translated to machine code, and how the choice of language and tools supports writing software.9 min answer →
1.2 Memory and storage
Module overview →- How do you convert between denary and binary, add binary numbers and use binary shifts?Converting between denary and binary (up to and including 8 bits), binary addition and the detection of overflow, and binary shifts and their effect.10 min answer →
- How are characters, images and sound represented in binary, and what affects their file size?Representing characters with ASCII and Unicode; representing images with pixels, colour depth, resolution and metadata; representing sound with sample rate, sample resolution and bit rate; and the effect on file size and quality.11 min answer →
- Why is data compressed, and what is the difference between lossy and lossless?The need for compression and the difference between lossy and lossless compression, with their typical uses.8 min answer →
- Why is hexadecimal used and how do you convert between binary, denary and hex?Why hexadecimal is used to represent numbers, and how to convert between binary, denary and hexadecimal.9 min answer →
- What is primary storage and why does a computer need RAM, ROM and virtual memory?The need for primary storage, the purpose and characteristics of RAM and ROM, the differences between them, and the need for virtual memory.9 min answer →
- Why does a computer need secondary storage and how do you choose the right type?The need for secondary storage, the common types (optical, magnetic, solid state) and how to choose a suitable device using capacity, speed, portability, durability, reliability and cost.9 min answer →
- How is the amount of data measured, and why is binary used?Why data must be represented in binary, the units of information (bit, nibble, byte, kB, MB, GB, TB, PB) and how to convert between them.8 min answer →
1.4 Network security
Module overview →- How can a system or network be protected against attacks?Methods to identify and prevent vulnerabilities: penetration testing, anti-malware software, firewalls, user access levels, passwords, encryption, physical security and network policies.9 min answer →
- What are the main forms of attack on a computer system or network?The forms of attack on computer systems and networks: malware, phishing, social engineering, brute-force attacks, denial of service, data interception and theft, SQL injection, and people as a weak point.10 min answer →
2.3 Producing robust programs and 2.4 Boolean logic
Module overview →- How do the logic operators AND, OR and NOT work, and how do you build a truth table?Boolean logic: the operators AND, OR and NOT, applying them to expressions, and constructing truth tables for simple logic statements including combinations of operators.10 min answer →
- How do you design a program that copes with unexpected input and is easy to maintain?Defensive design: anticipating misuse, input validation and sanitisation, authentication, and writing maintainable programs through comments, indentation and sensible naming.10 min answer →
- What are syntax errors and logic errors, and how do you tell them apart?The two main types of programming error: syntax errors and logic errors, what causes each, how they are found, and how they differ.9 min answer →
- How are the AND, OR and NOT operators drawn as logic gates and combined into circuits?Logic gates: the AND, OR and NOT gates and their symbols, reading and drawing simple logic circuit diagrams, and producing the truth table for a combination of gates.10 min answer →
- Why do we test programs, what kinds of testing are there, and what test data should you use?The purpose of testing, the difference between iterative and terminal (final) testing, and the types of test data (normal, boundary and erroneous or invalid), with how to choose suitable test data.10 min answer →
2.2 Programming fundamentals
Module overview →- What are the arithmetic, comparison and Boolean operators, and what do MOD and DIV do?The common operators: arithmetic (add, subtract, multiply, divide, exponent, MOD and DIV), comparison operators, and Boolean operators (AND, OR, NOT), and how they are used in expressions.10 min answer →
- How do you store and work with lists and tables of data, and query records with SQL?Using one-dimensional and two-dimensional arrays, the use of records to store structured data, and basic SQL (SELECT, FROM, WHERE) to search records in a database.11 min answer →
- What are the three programming constructs, and how do you use selection and the two kinds of iteration?The three basic programming constructs: sequence, selection (if and switch/case) and iteration (count-controlled for loops and condition-controlled while and do until loops), and when to use each.11 min answer →
- How do you manipulate strings and read from and write to text files?String manipulation (length, position, substring, concatenation and changing case, and converting between characters and character codes) and basic file handling (opening, reading, writing and closing text files).11 min answer →
- What are procedures and functions, how do parameters and return values work, and why use subprograms?The use of subprograms (procedures and functions), passing parameters into a subprogram, returning values from a function, local versus global variable scope, and generating random numbers.11 min answer →
- What are variables, constants and data types, and how do you choose and convert between them?The use of variables and constants, the common data types (integer, real, Boolean, character and string), choosing an appropriate data type, and casting (converting) between data types.10 min answer →
1.1 Systems architecture
Module overview →- How does the processor fetch and carry out a program instruction?The purpose of the CPU and the fetch-decode-execute cycle, the von Neumann architecture, and the function of common CPU components (ALU, CU, cache, registers including the MAR, MDR, Program Counter and Accumulator).10 min answer →
- What makes one CPU faster than another?How clock speed, the number of cores, and cache size and type affect the performance of the CPU.9 min answer →
- What is an embedded system and how does it differ from a general-purpose computer?The purpose and characteristics of embedded systems, with examples, and how they differ from general-purpose computer systems.8 min answer →
1.5 Systems software
Module overview →- What does an operating system do?The purpose and functions of the operating system: user interface, memory management and multitasking, peripheral management and drivers, user management, and file management.9 min answer →
- What is utility software and what maintenance tasks does it perform?The purpose of utility software, and the purpose of encryption software, defragmentation software, data compression and backup utilities (full and incremental).9 min answer →