Welcome to the Computer Systems Revision Hub
This page covers the fundamentals of how computers work. Because different exam boards structure their specifications slightly differently, the content here is tailored to support students studying Pearson Edexcel, AQA, OCR, and CIE (0478) Computer Science:
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Pearson Edexcel Students: These core topics map directly to Paper 1 (Principles of Computer Science).
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AQA Students: These revision modules align with Paper 2 (Computing Concepts).
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OCR Students: This content covers Component 1 (Computer Systems).
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CIE (0478) Students: This content covers Paper 1
Click on an image below to start studying!
Computer fundamentals for all exam bodies
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Number Systems: Binary, Denary, and Hexadecimal systems, along with conversions, additions, overflows, shifts, and Two's Complement.
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Data Representation: Text encoding (ASCII & Unicode), bitmaps, pixels, color depth, and resolution.
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Sound & Storage: Sound sample rates/depths, storage units (KiB, MiB, GiB, TiB), and calculating file sizes.
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Compression: Lossy and lossless compression types.
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Transmission & Methods: Data packets, serial vs. parallel transmission, and transmission modes (simplex, half-duplex, full-duplex, and USB).
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Error Detection: Parity check, checksum, echo check, and Automatic Repeat Request (ARQ).
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Security: Symmetric and asymmetric encryption.
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CPU & Architecture: CPU architecture, internal components (ALU, CU, and registers), system buses (Data, Address, Control), and the Fetch-Decode-Execute cycle.
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Storage & Devices: Input/output devices (sensors and actuators), primary storage (RAM & ROM), secondary storage (HDD, SSD, magnetic, optical, and solid-state), virtual memory, and cloud storage.
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Networking Hardware & Addressing: Network Interface Cards (NIC), MAC addresses, IP addresses (IPv4 vs. IPv6), and routers.
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Software Types & OS: Types of software, system software, application software, and the core role of the operating system (managing memory, processors, devices, security, and files).
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Low-Level Systems & Interrupts: Interrupt handling alongside high-level and low-level programming languages.
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Translators & Development: Compilers, interpreters, assemblers, and IDE features.
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Web & Protocols: Internet vs. World Wide Web (WWW), web browsers, DNS, URL structures, HTTP/HTTPS, and cookies.
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Emerging Technologies: Digital currency and blockchain concepts.
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Cybersecurity: Brute-force & DoS attacks, malware, phishing, pharming, firewalls, proxy servers, SSL/TLS handshakes, digital certificates, and ethics & plagiarism.
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Automated Systems & Control: Sensor types, ADC/DAC conversions, automated control systems, and feedback loops.
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Robotics: Characteristics of robotics, controllers, actuators, and applications across industry, transport (drones), medicine, and agriculture.
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AI & Expert Systems: Artificial Intelligence, expert systems (inference engines, knowledge bases, rules bases), and machine learning concepts.
Additional content for OCR Component 1
Additional content for AQA Paper 2
Additional content for Pearson Edexcel Paper 1
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