What hardware do I need to know for Eduqas GCSE Computer Science?

You need the purpose of the CPU and its components (the ALU, control unit and registers), the fetch-decode-execute cycle in order, the von Neumann architecture, and the three factors that affect CPU performance (clock speed, number of cores and cache). You also need primary storage (RAM, ROM and virtual memory), the need for and three types of secondary storage (magnetic, optical and solid state), cloud storage with its advantages and disadvantages, embedded systems, and input and output devices including sensors and actuators.

What is the difference between the von Neumann architecture and the fetch-decode-execute cycle?

The von Neumann architecture is the design of the computer: a single memory holds both instructions and data, reached over a shared bus. The fetch-decode-execute cycle is the process the CPU repeats to run a program on that architecture: it fetches the next instruction from memory, decodes it in the control unit, then executes it, and repeats. The architecture is the layout; the cycle is the action that runs on it.

Why does adding more cores not double the speed of a computer?

More cores let the CPU process more instruction streams at once, which speeds up tasks that can be split across cores or several programs running together. But many programs are sequential, meaning each step depends on the previous one, so they cannot be split and run on a single core. Cores also share resources such as memory and cache, and software must be written to use multiple cores, so the real speed-up is usually less than the number of cores.

How do I choose the right secondary storage device in the exam?

Match the device to the use by weighing capacity, speed, portability, durability, reliability and cost. Magnetic hard disks give high capacity at low cost but have moving parts; optical discs are cheap for distributing media; solid-state storage is fast, robust and portable but costs more per gigabyte. State the factors that matter for the scenario, recommend a type, and justify it against those factors rather than giving a bare answer.

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Hardware and architecture overview - Eduqas GCSE Computer Science

A deep-dive guide to the hardware and architecture topic of Eduqas GCSE Computer Science: the CPU and the fetch-decode-execute cycle, von Neumann architecture and registers, the factors affecting CPU performance, primary and secondary storage, cloud storage, embedded systems, and input and output devices.

Generated by Claude Opus 4.812 min readEduqas GCSE CS 1.1 HardwareUpdated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

The CPU and how it runs a program
What makes one CPU faster than another
Storage: primary, secondary and cloud
Embedded systems and input/output
How to revise this topic

The hardware and architecture topic is the foundation of Component 1: it explains how a computer is built and how the processor runs a program. This guide ties the whole topic together; each section links to a focused answer page with worked Eduqas exam questions.

The CPU and how it runs a program

The CPU (central processing unit) processes data by carrying out program instructions. Its ALU does arithmetic and logic, its control unit decodes instructions and sends control signals, and its registers are tiny, very fast stores for the values it is working on right now. The four named registers are the Program Counter (address of the next instruction), the MAR (the address being accessed), the MDR (the data or instruction in transit) and the accumulator (the result of ALU calculations).

The processor runs every program through the fetch-decode-execute cycle: it fetches the next instruction from memory (using the Program Counter), decodes it in the control unit, then executes it, and repeats. This runs on the von Neumann architecture, in which a single memory holds both instructions and data, reached over a shared bus. Full detail and a worked trace of a single instruction are on the CPU and fetch-decode-execute page.

What makes one CPU faster than another

Three factors affect CPU performance. Clock speed is the number of cycles per second (measured in gigahertz), so more cycles means more instructions processed. The number of cores is how many instruction streams the CPU can run at once, but doubling the cores rarely doubles real speed because many programs are sequential and cores share resources. Cache is small, very fast memory that holds frequently used instructions and data, so a larger cache means more cache hits and less waiting for slow RAM. The worked comparison is on the CPU performance page.

Storage: primary, secondary and cloud

Primary storage is the memory the CPU accesses directly: RAM (volatile, holds what is in use), ROM (non-volatile, holds the start-up instructions) and virtual memory (secondary storage used as extra RAM when RAM is full). Secondary storage keeps files permanently and comes in three types: magnetic (hard disks: high capacity, low cost), optical (CD, DVD, Blu-ray: cheap distribution) and solid state (flash: fast, robust, portable). You choose a device by weighing capacity, speed, portability, durability, reliability and cost. See the primary and secondary storage page.

Cloud storage keeps your files on a provider's remote servers, accessed over the internet. It offers access from anywhere, provider-managed backups and easy scaling, but depends on a connection, has ongoing costs, and puts data in a third party's hands. This is covered alongside embedded systems on the cloud storage and embedded systems page.

Embedded systems and input/output

An embedded system is a computer built into a larger device to do one dedicated task (a washing machine controller, a car's engine management), so it is typically small, cheap, low-power and reliable with a fixed program, unlike a general-purpose computer. Input devices send data into the computer (keyboard, mouse, microphone, and sensors for automatic systems); output devices present results (monitor, printer, speakers, and actuators that act on the environment). Choosing devices means matching them to the system and the user, including for accessibility. See the input and output devices page.

How to revise this topic

Learn the cycle and the registers cold. Be able to name the three stages in order and trace one instruction, stating which register holds what.
Explain, do not just list, the performance factors. The marks are in saying why clock speed, cores and cache change performance, especially why cores do not simply multiply speed.
Drill the comparison definitions. RAM versus ROM, the three storage types, and cloud versus local storage are recurring contrast questions where exact wording scores.
Practise scenario choices. Choosing storage, or input and output devices for a weather station or an accessible system, rewards matching the device to the need and justifying it.

Test yourself with the hardware and architecture quiz, then work through each dot-point page for the full worked exam questions.