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England · OCRQ&A
Computer ScienceQ&A by dot point
A short Q&A bank for every England Computer Science syllabus dot point. Each question and answer is drawn directly from our worked dot-point page, so you can scan key concepts before opening the long-form answer.
2.1 Algorithms
- The principles of computational thinking: abstraction, decomposition and algorithmic thinking, and how each is used to analyse a problem and design a solution.3Q&A pairs
- 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.3Q&A pairs
- 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.3Q&A pairs
- Standard sorting algorithms: bubble sort, insertion sort and merge sort, how each works step by step, and how they compare in approach and efficiency.3Q&A pairs
- 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.2Q&A pairs
1.3 Computer networks, connections and protocols
- 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).3Q&A pairs
- Types of network (LAN and WAN), the factors that affect network performance, and the difference between client-server and peer-to-peer networks.3Q&A pairs
- Common network protocols (TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP), the concept of layers and the benefits of using them.3Q&A pairs
- Wired (Ethernet) versus wireless (Wi-Fi) connections and their relative advantages and disadvantages, and the role of encryption in wireless networks.3Q&A pairs
1.6 Ethical, legal, cultural and environmental impacts
- 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.3Q&A pairs
- 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.4Q&A pairs
- 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.4Q&A pairs
- 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).3Q&A pairs
- 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.4Q&A pairs
2.5 Programming languages and IDEs
- 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.3Q&A pairs
- 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.3Q&A pairs
- 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.3Q&A pairs
- 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.3Q&A pairs
1.2 Memory and storage
- Converting between denary and binary (up to and including 8 bits), binary addition and the detection of overflow, and binary shifts and their effect.4Q&A pairs
- 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.3Q&A pairs
- The need for compression and the difference between lossy and lossless compression, with their typical uses.3Q&A pairs
- Why hexadecimal is used to represent numbers, and how to convert between binary, denary and hexadecimal.3Q&A pairs
- The need for primary storage, the purpose and characteristics of RAM and ROM, the differences between them, and the need for virtual memory.3Q&A pairs
- 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.4Q&A pairs
- 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.3Q&A pairs
1.4 Network security
- Methods to identify and prevent vulnerabilities: penetration testing, anti-malware software, firewalls, user access levels, passwords, encryption, physical security and network policies.3Q&A pairs
- 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.3Q&A pairs
2.3 Producing robust programs and 2.4 Boolean logic
- Boolean logic: the operators AND, OR and NOT, applying them to expressions, and constructing truth tables for simple logic statements including combinations of operators.4Q&A pairs
- Defensive design: anticipating misuse, input validation and sanitisation, authentication, and writing maintainable programs through comments, indentation and sensible naming.3Q&A pairs
- The two main types of programming error: syntax errors and logic errors, what causes each, how they are found, and how they differ.3Q&A pairs
- 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.3Q&A pairs
- 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.4Q&A pairs
2.2 Programming fundamentals
- 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.3Q&A pairs
- 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.3Q&A pairs
- 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.3Q&A pairs
- 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).4Q&A pairs
- 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.3Q&A pairs
- 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.3Q&A pairs
1.1 Systems architecture
- 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).3Q&A pairs
- How clock speed, the number of cores, and cache size and type affect the performance of the CPU.3Q&A pairs
- The purpose and characteristics of embedded systems, with examples, and how they differ from general-purpose computer systems.3Q&A pairs
1.5 Systems software
- The purpose and functions of the operating system: user interface, memory management and multitasking, peripheral management and drivers, user management, and file management.3Q&A pairs
- The purpose of utility software, and the purpose of encryption software, defragmentation software, data compression and backup utilities (full and incremental).3Q&A pairs