AQA Computer Science GCSE
Data Representation – Revision
This unit appears on Paper 2.
There will be some knowledge based questions, but also plenty of questions where you have to do simple calculations or know how to work something else. Although you need to learn definitions, it's more important to be able to use the knowledge in a practical way.
There will be questions on binary and converting between file sizes (Bytes, MB etc...) for sure. Quite a lot of the marks are quite straightforward questions from this unit and its worth making sure you can deal with anything that gets thrown at you.
Revision materials
Syllabus content – a slightly edited version of the syllabus document showing what you need to know in some detail
Booklet to print – an active way to revise the key knowledge required
Key definitions, knowledge and skills – a summary of the things you need to learn all on one slide
There is a separate set of slides on compression revision.
Compression – a summary
There are online quizes for both parts of the unit.
Binary, hexadecimal and decimal numbers quiz
Text, images and sound representation quiz
Questions
It's useful to work through sample questions for the skills elements of this unit. You'll find the basics and some questions on each of the pages, but here's four pages of sample questions dealing with everything from binary to image and sound representation - primarily involving lots of calculations.
Remember, Computer Science is a none calculator subject. You have to do the maths by hand.
Revision Questions – you might want to print this
Answers
I'll also give you the answers. But try to resist the temptation to cheat. Do the questions, then check the answers. Preparation works better that way round - trust me.
If I've made a mistake with any of the answers let me know! I did double check them (and found two errors – one of which was a simple maths error – so really do do that thing you teachers say and check your answers too...)
Worked Answers
And I went through and showed my working by hand as well. This has the advantage that you can see exactly how I did the questions – the working out that I used. By looking back at the teaching pages (on the left) you should find the same methods there.
You'll see that I've made clear what the answer is where necessary (by crossing my working out through on question 2, for example) and that I've tended to include units even when they aren't necessary.
Also notice that b is the official abbreviation for bits and B for Bytes. These are in the syllabus, so I can use them without needing to write the long form – and I've done that at times.