That Blue Square Thing

AQA Computer Science GCSE

September 2020: This page is the for the 2022 exam version of the AQA Computer Science GCSE course. This is for Year 10 teaching in September 2020.
These pages were copied over from the old syllabus and will get updated as I work through the new one. That means they won't always be totally up to date and I might miss something - check the updated date at the bottom of the page.

Computer Systems - Systems Architecture

What goes on inside the box?

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 (, You may want to look at the large version of the image (zoom in) to see more detail on the board.

There's a really interesting article about the supply chain for a Huawei motherboard 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 start.

PDF iconVon Neumann Architecture - slides from class

PDF iconThe von Neumann Architecture - notes and activities

Click on the thumbnail to get a diagram of the von Neumann architecture that you can label.

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.