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WalesComputer Science

Unit 1: Hardware and communication

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What are input and output devices, and how do you choose suitable devices for a task?

The purpose of input and output devices, examples of each, and choosing appropriate input and output devices for a given situation.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on input and output devices, covering the purpose of input devices and output devices, common examples of each, the idea of the computer as an input-process-output system, and how to choose suitable devices for a given situation.
8 min answer →

What is the difference between RAM and ROM, and what is virtual memory used for?

The purpose and characteristics of RAM and ROM, the difference between volatile and non-volatile memory, and the purpose of virtual memory.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on memory, covering the purpose and characteristics of RAM and ROM, the meaning of volatile and non-volatile, the role of the BIOS in ROM, and how virtual memory uses secondary storage to extend RAM when it is full.
8 min answer →

What factors affect how fast a processor performs, and how do clock speed, cores and cache change performance?

The factors affecting processor performance: clock speed, the number of cores, and the amount and use of cache memory.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on processor performance, covering how clock speed, the number of cores and the amount of cache memory each affect how fast a CPU can process instructions, and why simply increasing one factor does not always make a computer faster.
8 min answer →

Why is secondary storage needed, and how do magnetic, optical and solid-state storage compare?

The need for secondary storage, the characteristics of magnetic, optical and solid-state storage, and calculating storage requirements and capacity.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on secondary storage, covering why secondary storage is needed, the characteristics, advantages and disadvantages of magnetic, optical and solid-state storage, and calculating how many files of a given size fit in a given storage capacity.
8 min answer →

What is the CPU made of, and what is the von Neumann stored-program architecture?

The purpose and main components of the CPU (the ALU, the control unit and registers) and the von Neumann stored-program architecture.
A focused answer to the WJEC GCSE Computer Science Unit 1 content on the CPU and von Neumann architecture, covering the purpose of the CPU, the roles of the arithmetic logic unit, the control unit and registers, and the von Neumann stored-program model where instructions and data share the same memory.
8 min answer →

What happens during the fetch-decode-execute cycle, and what is the role of each register?

The fetch-decode-execute cycle and the roles of the registers used in it (the program counter, memory address register, memory data register and accumulator).
A focused answer to the WJEC GCSE Computer Science Unit 1 content on the fetch-decode-execute cycle, covering the three stages of fetch, decode and execute, the roles of the program counter, memory address register, memory data register and accumulator, and how the cycle repeats to run a program.
8 min answer →