Computer Science
IGCSE · 28 topics available
Chapter 1 · Data Representation
Number Systems: Binary and Hexadecimal
Discover how computers store numbers using base-2 binary and base-16 hexadecimal, and learn to convert between them and everyday denary.
OpenText, Sound and Images
How computers turn characters, sound and images into binary using character sets, sampling and pixels.
OpenData Storage and Compression
Learn the units of storage, why files are compressed, and the difference between lossless and lossy methods like RLE and JPEG.
OpenChapter 2 · Data Transmission
Types and Methods of Data Transmission
Compare serial and parallel transmission, simplex and duplex modes, and see how data packets travel by packet switching.
OpenError Detection Methods
Understand how parity checks, checksums, echo checks and check digits spot errors when data is sent from one device to another.
OpenEncryption
Learn how encryption scrambles plaintext into ciphertext, and compare symmetric and asymmetric keys that keep data private.
OpenChapter 3 · Hardware
Computer Architecture and the CPU
How the CPU runs programs using the fetch-decode-execute cycle, registers, buses and the Von Neumann model of stored data.
OpenInput and Output Devices
How input devices send data into a computer and output devices present results, with common examples and how to match a device to a task.
OpenMemory, Storage and Virtual Memory
The difference between volatile RAM and non-volatile ROM, primary versus secondary storage, and how virtual memory uses secondary storage.
OpenChapter 4 · Software
System and Application Software
The difference between system software that runs the computer and application software that helps users do tasks, and the role of the operating system.
OpenProgramming Languages and Translators
High-level versus low-level languages, and how compilers, interpreters and assemblers translate source code into machine code the CPU can run.
OpenChapter 5 · The Internet and its Uses
The Internet and the World Wide Web
The internet is a global network of connected computers; the World Wide Web is the collection of web pages that runs on it. They are not the same thing.
OpenDigital Currency
Digital currency exists only electronically, with no physical notes. Blockchain keeps a shared, tamper-evident record of transactions.
OpenCyber Security
Cyber security protects data and systems from threats like phishing, pharming and brute-force attacks, using firewalls and strong passwords.
OpenChapter 6 · Automated and Emerging Technologies
Automated Systems
An automated system uses sensors to gather data, a microprocessor to make decisions, and actuators to act, running with little human control.
OpenRobotics
Robotics combines sensors, a control unit and moving parts so a machine can sense its surroundings and carry out physical tasks automatically.
OpenArtificial Intelligence
AI lets machines mimic human thinking. Expert systems use a rule base and inference engine; machine learning improves from training data.
OpenChapter 7 · Algorithm Design and Problem-Solving
Program Development Life Cycle
The program development life cycle breaks software creation into stages: analysis, design, coding and testing, helping produce reliable programs.
OpenPseudocode and Flowcharts
Pseudocode and flowcharts are two ways to plan an algorithm clearly before writing real program code.
OpenSearching and Sorting Algorithms
Searching finds an item in a list; sorting puts items into order. IGCSE covers linear and binary search, and bubble and insertion sort.
OpenValidation, Verification and Testing
Validation checks whether data is reasonable, verification checks it was entered accurately, and testing checks that a program works correctly.
OpenChapter 8 · Programming
Programming Concepts
Core programming concepts include variables and constants, data types, sequence, selection, iteration, and totalling and counting.
OpenArrays and Data Structures
An array is a data structure that stores many values of the same type under one name, each reached by an index.
OpenProcedures and Functions
Procedures and functions are named blocks of code (subroutines). A function returns a value; a procedure does not.
OpenChapter 9 · Databases
Chapter 10 · Boolean Logic
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