That Blue Square Thing

Syllabus content:
PDF iconUnit 4 content - PDF doc to download and print
Note: this syllabus content is a slightly amended version of the one published freely on the web by AQA. I have made very minor adjustments to remove some content less suitable for students to use and it is presented here simply to allow the children I teach to download a usable copy of the syllabus content. It is copyright AQA and reproduced here simply to make access easier for students. No attempt to claim copyright is being made, although I could have copied the text into my own interpretation...

AQA Computer Science GCSE

February 2019: this area of the site is being built just now. There are areas where there is no content yet. That will get added over the next 6 months or so.

Computer Systems

This area is all about the ways in which computers work. That includes what goes on inside the "black box" of the computer system and how things fit together.

I break the syllabus here down into six parts, although these are a little different to how the syllabus actually reads. It will be developed as I teach it in late 2018/early 2019:

  1. Hardware and Software - on this page
  2. Boolean logic - there is some more to add to this
  3. Software types
  4. Systems architecture
  5. Fetch-Execute cycle
  6. Storage types
  7. Embedded systems

There are some parts of this unit which crossover with the last part of Unit 2 - the ways in which programming languages work.

Hardware and Software

Computer systems are made up of hardware and software.

Hardware is simply any physical component that makes up the computer system. This might include the monitor, keyboard and mouse on a PC as well as the circuit boards and memory inside the machine. Not every system has all of this hardware - simple, embedded systems (such as those in a microwave oven or a supermarket till) might have much less hardware that a user can interact with.

Software is the programs that run on the hardware.

Input and Output Devices

Some elements of hardware are designed to be interacted with by users. This can be to either input data into the system or to receive outputs from the system. These types of hardware are called I/O devices - meaning input/output devices.

Input devices allow users to input data into the computer system. These devices include keyboards, mice, touchscreens, microphones, fingerprint readers, cameras, game controllers and any other type of device where data can be inputed via buttons, switches or in any other way.

Output devices are any piece of hardware which allows the computer system to provide feedback of some kind to the user. Most simply these include screens, printers and speakers/headphones. Any kind of LED or sound is also an output device, as is the movement received from a device such as a game controller (an example of haptic feedback). Embedded systems such as the computers in dishwashers will provide feedback in a different way to a standard computer system.

Note that some I/O devices will be used for both input and output - for example, a touch screen or a game controller.