Computer Science revision notes

One chapter for each section of the 2210 syllabus, with worked examples. Read a chapter, then practise it with real past-paper questions.

1. 1Data RepresentationHow computers store numbers, text, sound and images in binary, how hexadecimal and two's complement work, and how files are measured and compressed.22 min read
2. 2Data TransmissionHow data travels as packets, the five methods of transmission, how errors are detected, and how encryption keeps data private.22 min read
3. 3HardwareThe CPU and the fetch-decode-execute cycle, input and output devices and sensors, primary and secondary storage, virtual and cloud storage, and network hardware.28 min read
4. 4SoftwareSystem and application software, what an operating system does, how interrupts are handled, high-level and low-level languages, compilers, interpreters and IDEs.12 min read
5. 5The Internet and its UsesThe internet and the world wide web, URLs and browsers, cookies, digital currency and blockchain, and the cyber security threats and the measures that stop them.16 min read
6. 6Automated and Emerging TechnologiesHow automated systems work, what makes something a robot, and how artificial intelligence, expert systems and machine learning simulate intelligent behaviour.9 min read
7. 7Algorithm Design and Problem SolvingThe program development life cycle, structure diagrams, flowcharts and pseudocode, the standard algorithms (counting, totalling, bubble sort, linear search), validation, verification, test data and trace tables.14 min read
8. 8ProgrammingVariables, data types, selection and loops, strings, operators, procedures and functions, library routines, arrays and file handling, with the Cambridge pseudocode and Python side by side.7 min read
9. 9DatabasesFields, records and primary keys in a single-table database, the data types, and the SQL commands SELECT, FROM, WHERE, ORDER BY, SUM and COUNT.4 min read
10. 10Boolean LogicThe six logic gates and their truth tables, and how to write an expression for a circuit, complete a truth table, draw a circuit from an expression, and build a circuit from a problem statement.9 min read