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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.
Algorithms and computational thinking
- Computational thinking: abstraction, decomposition and algorithmic thinking, and how these techniques are used to break down and solve a problem.3Q&A pairs
- Designing, expressing and tracing algorithms using pseudocode and flowcharts, and using a trace table to follow an algorithm step by step.3Q&A pairs
- The logic operators AND, OR and NOT, their logic gates and truth tables, and combining them in simple logic circuits and Boolean expressions of up to three inputs.3Q&A pairs
- The linear search and binary search algorithms, how each works, the requirement that binary search needs sorted data, and how their efficiency compares.3Q&A pairs
- The bubble sort and merge sort algorithms, how each puts a list into order, and how their efficiency on large lists compares.3Q&A pairs
Data representation and storage
- Binary addition of two 8-bit numbers including carrying and overflow, and binary shifts (left and right) and their effect of multiplying or dividing by powers of two.4Q&A pairs
- How text is represented using character sets, the ASCII character set, the need for and nature of Unicode, and how a character maps to a binary code.3Q&A pairs
- The purpose of compression, the difference between lossy and lossless compression, and how to choose the appropriate type for a given scenario.3Q&A pairs
- Number systems: binary, denary and hexadecimal, and how to convert between all three, including why hexadecimal is used as a shorthand for binary.3Q&A pairs
- Signed and unsigned binary, and the use of two's complement to represent negative integers, including converting between two's complement and denary for 8-bit numbers.3Q&A pairs
- The units of data (bit, nibble, byte, kilobyte, megabyte, gigabyte, terabyte), how images are stored as pixels (resolution and colour depth), how sound is sampled (sample rate and bit depth), and calculating file sizes.3Q&A pairs
Hardware and architecture
- Cloud storage and its advantages and disadvantages, and the characteristics and uses of embedded systems compared with general-purpose computers.3Q&A pairs
- The purpose of the CPU, the fetch-decode-execute cycle, the von Neumann architecture, and the function of the common CPU components and registers (ALU, control unit, PC, MAR, MDR, accumulator).3Q&A pairs
- The factors that affect CPU performance: clock speed, the number of cores, and the size and use of cache memory, and how each one changes how quickly programs run.3Q&A pairs
- The purpose of input and output devices, common examples (including sensors and actuators), and how to choose suitable devices for a given system or user.3Q&A pairs
- Primary storage (RAM, ROM and virtual memory), the need for and types of secondary storage (magnetic, optical and solid state), and the factors used to choose a storage device.3Q&A pairs
Impacts and legislation
- The environmental impacts of digital technology, including energy consumption, the resources used to make devices, electronic waste (e-waste), and reuse and recycling.3Q&A pairs
- The ethical, cultural and social impacts of digital technology, including the digital divide, the effect on employment and working practices, and issues such as misinformation and online behaviour.4Q&A pairs
- The relevant legislation: the Data Protection Act, the Computer Misuse Act, and the Copyright, Designs and Patents Act, including what each covers and the offences under each.4Q&A pairs
- Privacy and the impact of data collection, tracking and surveillance, including cookies and location data, and the balance between privacy, security and convenience.3Q&A pairs
Networks and security
- The common cybersecurity threats: malware, phishing, social engineering, brute-force attacks, denial-of-service attacks and SQL injection, and how each one works.3Q&A pairs
- LANs and WANs and the benefits and drawbacks of networking, and the bus, star and mesh network topologies with their advantages and disadvantages.3Q&A pairs
- The methods used to protect a system (firewalls, encryption, passwords and biometrics), and data management including the need for and types of backup.3Q&A pairs
- The internet, the World Wide Web and DNS, and the purpose of the common protocols: TCP/IP, HTTP, HTTPS, FTP, SMTP, POP and IMAP.3Q&A pairs
- The concept of a layered model for network protocols, the role of layers, and the advantages of using a layered approach.3Q&A pairs
- Wired and wireless connections and their advantages and disadvantages, and the purpose of common network hardware: the network interface card (NIC), switch, router and wireless access point.3Q&A pairs
Programming
- Variables and constants, the common data types (integer, real, Boolean, character, string), and the arithmetic, relational and logical operators used in programs.3Q&A pairs
- Arrays as a data structure: declaring and using one-dimensional arrays, accessing elements by index, and iterating through an array with a loop, with awareness of two-dimensional arrays.2Q&A pairs
- High-level and low-level languages, machine code and assembly language, the three translators (compiler, interpreter and assembler), and the features of an integrated development environment (IDE).3Q&A pairs
- The purpose and functions of an operating system (memory management, multitasking, peripheral management, the user interface, and security and user management) and the role of common utility software.3Q&A pairs
- The three programming constructs: sequence, selection (if and nested if) and iteration (count-controlled and condition-controlled loops), and when to use each.5Q&A pairs
- String handling (length, indexing, substrings, concatenation, case conversion), input validation (presence, range, length, type and format checks), and how programs are written and tested in the Component 2 on-screen exam.5Q&A pairs
- Subprograms (procedures and functions), the difference between them, parameters and arguments, local and global variables, and why subprograms make programs easier to write and maintain.3Q&A pairs