That Blue Square Thing

AQA Computer Science GCSE

This page is up to date for the new AQA 8525 syllabus for the 2022 exam.

Computer Systems - Systems Architecture

What goes on inside the box?

I think it helps to get an idea of what's inside a standard computer before we get into the theory and so on.

Ideally you'd take a computer apart to have a look as part of this. Do take care if you do this at home! Ask permission, use an old computer, unplug it and look up what else you need to do to be safe on the internets before you start. You can break things far too easily...

>PDF iconThe Motherboard - slides from class

PDF iconMotherboard basics - notes on the main components on the motherboard

PDF iconMotherboard Image to label - photo to label

PDF iconTransistors as switches - slides from class

The original image of the motherboard can be found on Wikimedia Commons. The terms of use are: Rainer Knäpper, Free Art License ( link), link. You may want to look at the large version of the imagewiki link (zoom in) to see more detail on the board.

There's a really interesting article about the supply chain for a Huawei motherboardwiki link that you might want to take a look at. It demonstrates the way that the component industry is globalised. (BBC, 21 May 2019)

The von Neumann Architecture and the CPU

thumbnail of CPU diagram

The von Neumann architecture describes the basic way in which a general purpose computer is organised. It was first described by John von Neumann in 1945. von Neumann was a really interesting chap. You might want to spend five minutes finding a little bit more out about him: Wikipedia is a good place to startwiki link.

PDF iconVon Neumann Architecture - slides from class

PDF iconThe von Neumann Architecture - notes and activities

thumbnail of CPU diagram

As part of his architecture, von Neumann described how the CPU would work.

You need to know about some of the components inside the CPU:

PDF iconInside the CPU - slides from class

PDF iconInside the CPU - notes on the elements

If you need a diagram of the simplified structure of the CPU you can click on the thumbnail to get a larger version.

For more on how the CPU works to decode and execute instructions, see the Fetch-Execute page.