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Computer ScienceQ&A by dot point
A short Q&A bank for every Wales 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.
Unit 1: Algorithms and programming principles
- Computational thinking through decomposition and abstraction, what an algorithm is, and expressing algorithms using flowcharts and pseudocode.2Q&A pairs
- Boolean logic using the AND, OR and NOT operators, constructing truth tables, the logic gates, and simplifying simple logic expressions.2Q&A pairs
- The three programming constructs (sequence, selection and iteration), the use of variables and constants, and arithmetic, relational and logical operators.2Q&A pairs
- The linear search and binary search algorithms, how each works, and the conditions under which each is suitable.2Q&A pairs
- The bubble sort and merge sort algorithms, how each puts data into order, and the relative efficiency of the two methods.2Q&A pairs
- The use of subprograms (procedures and functions) and parameters, and the benefits of a modular, structured approach to programming.2Q&A pairs
Unit 1: Communication and networks
- IP addresses and MAC addresses, the purpose of the Domain Name System (DNS), and how data is routed across the internet.2Q&A pairs
- The hardware needed for networking (network interface card, switch, router, transmission media), wired versus wireless connections, bandwidth, and how data is sent in packets.2Q&A pairs
- The purpose of computer networks, the difference between LANs and WANs, client-server and peer-to-peer models, and common network topologies.2Q&A pairs
- The purpose of protocols, common protocols (TCP/IP, HTTP and HTTPS, FTP, SMTP), and why network communication is organised into layers.2Q&A pairs
Unit 1: Hardware and communication
- The purpose of input and output devices, examples of each, and choosing appropriate input and output devices for a given situation.2Q&A pairs
- The purpose and characteristics of RAM and ROM, the difference between volatile and non-volatile memory, and the purpose of virtual memory.2Q&A pairs
- The factors affecting processor performance: clock speed, the number of cores, and the amount and use of cache memory.2Q&A pairs
- The need for secondary storage, the characteristics of magnetic, optical and solid-state storage, and calculating storage requirements and capacity.2Q&A pairs
- The purpose and main components of the CPU (the ALU, the control unit and registers) and the von Neumann stored-program architecture.2Q&A pairs
- 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).2Q&A pairs
Unit 1: Security and data management
- Common cyber security threats, including malware, phishing, social engineering, brute-force attacks, denial-of-service attacks, SQL injection and data interception.2Q&A pairs
- Methods of protecting systems and networks, including firewalls, encryption, authentication, anti-malware, penetration testing, network policies and managing cookies.2Q&A pairs
Unit 1: Organisation and structure of data
- Data security and integrity processes, including backups, archiving, and methods of keeping data accurate and consistent.2Q&A pairs
- The common data types, the use of data structures such as arrays and records, and the difference between validation and verification.2Q&A pairs
- 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.2Q&A pairs
Unit 1: Data representation and data types
- 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.2Q&A pairs
- 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.2Q&A pairs
- 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.2Q&A pairs
- The need for compression, the difference between lossy and lossless compression, and how run-length encoding compresses data.2Q&A pairs
- The hexadecimal number system, why hexadecimal is used as a shorthand for binary, and converting between hexadecimal, binary and denary.2Q&A pairs
- Representing bitmap images as pixels, the meaning of resolution and colour depth, calculating the file size of an image, and the role of metadata.2Q&A pairs
- Representing signed (negative and positive) integers in binary using the sign and magnitude method and the two's complement method, and converting between them.2Q&A pairs
- 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.2Q&A pairs
Unit 1: Software and system development
- Low-level and high-level programming languages, the need for translators, and the differences between assemblers, compilers and interpreters.2Q&A pairs
- The purpose of the operating system and its main functions: managing memory, processes, peripherals and files, providing a user interface, and managing security.2Q&A pairs
- The need for different types of software, and the difference between system software and application software with examples of each.2Q&A pairs
- The purpose of utility software and the function of common utilities, including antivirus, backup, file compression and disk defragmentation.2Q&A pairs
Unit 1: Ethical, legal and environmental impacts
- The environmental impacts of digital technology (energy use, e-waste and resources) and its social impacts, including the effects of e-commerce.2Q&A pairs
- The main legislation governing computer use (data protection, the Computer Misuse Act and copyright law) and the ethical and cultural issues raised by computing.2Q&A pairs
- The stages of the software development life cycle (analysis, design, development, testing, evaluation and maintenance) and the use of test plans and test data.3Q&A pairs
- 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).3Q&A pairs