What are the main parts of a computer's architecture, and what is the environmental impact of using computers?
Computer architecture: the role of the processor, memory and the buses that connect them; and the environmental impact of the manufacture, use and disposal of computer systems.
An SQA National 5 Computing Science answer on computer architecture and environmental impact, covering the role of the processor (with its registers and arithmetic logic unit and control unit), main memory, and the address and data buses, and the environmental impact of manufacturing, running and disposing of computer systems.
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What this key area is asking
The SQA wants you to describe the main parts of a computer's architecture - the processor, the memory and the buses that connect them - and to discuss the environmental impact of manufacturing, using and disposing of computer systems.
The processor
The processor is where the actual work of running a program happens: every calculation, comparison and decision in your code is carried out here. The control unit keeps the system in step, and the registers give the processor instant access to the values it is currently using.
Memory and buses
Memory and processor are not the same thing: the processor does the work, while memory holds what the processor needs. They are joined by the buses, which is why a question may ask you to explain how data gets from memory to the processor - the address bus selects where, and the data bus carries what.
The environmental impact of computer systems
This is a discussion topic as much as a recall one. A good answer recognises that the impact is not only about electricity while a device is switched on, but also the materials and energy used to build it and the waste created when it is discarded, and then offers practical ways to reduce that impact.
Why this key area matters
Understanding the architecture explains how a program actually runs on hardware: your high-level code becomes instructions the processor fetches from memory over the buses and executes. The environmental impact links computing to wider society, which the SQA examines because responsible use of technology is part of being a computing scientist, not just writing code.
How this key area is examined
Questions ask you to describe the role of the processor, memory or buses, state what the address and data buses carry, or discuss the environmental impact of computer systems and how to reduce it. Keep the three architecture parts distinct, name the address and data buses correctly, and for the environment cover manufacture, use and disposal plus at least one practical reduction.
For the official course specification
The SQA publishes the full National 5 Computing Science course specification, specimen question papers and coursework tasks at sqa.org.uk. Always revise from the current specification and SQA past papers, because question style and terminology are board-specific.
Exam-style practice questions
Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
SQA N5 style3 marksDescribe the role of the processor and main memory in a computer system, and state what the buses are used for.Show worked answer →
Three marks: one for the processor, one for memory and one for the buses.
Processor: it carries out the instructions of a program, performing calculations and logical decisions and controlling the rest of the system.
Main memory: it stores the program instructions and data currently in use so the processor can fetch them quickly.
Buses: they are the connections that carry signals between the processor and memory - the address bus carries the location of data and the data bus carries the data itself.
Markers reward a correct role for each part. Saying the processor "does the work", memory "holds what is in use", and buses "carry data and addresses between them" earns the marks.
SQA N5 style4 marksDescribe two environmental impacts of computer systems and one way the impact can be reduced.Show worked answer →
Up to four marks: two impacts plus a way to reduce, with detail.
Impact 1: making computers uses energy and raw materials, including scarce metals, which has an environmental cost.
Impact 2: computers consume electricity while in use, and discarded computers create electronic waste (e-waste) that can be harmful if sent to landfill.
Reducing the impact: recycling old equipment and reusing components, switching devices off or using low-power/standby settings, and keeping devices longer instead of replacing them often.
Markers reward two genuine impacts (manufacture, energy use in use, or disposal/e-waste) and at least one sensible reduction such as recycling or saving energy.
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