GCSE Computing Revision Booklet
This booklet has been created to provide an overview of each of the topics that you need to revise. Each section is broken down and guidance given on what you need to know. Use it in conjunction with your own revision techniques, e.g. mindmaps, to prepare for the exam.
Fundamentals of Computer Systems
You need to be able to: (a) define a computer system (b) describe the importance of computer systems in the modern world (c) explain the need for reliability in computer systems (d) explain the need for adherence to suitable professional standards in the development, use and maintenance of computer systems (e) explain the importance of ethical, environmental and legal considerations when creating computer systems.
What is a computer system? At its very basic, a computer system nothing more than an input, a processor and an output.
A computer system will usually have some storage capability and more often now – a way of communicating with other devices. Computers are all around us and I’m not just talking about your desktop or laptop computer. Your “smartphone”, your games console, your ipad, even your Sky+ or freeview recorder is a computer system of sorts.
3 Computer systems are integral parts of our lives. Think about all the computer systems you or your parents use on a daily or weekly basis:
Running washing programmes and sensing when clothes are dry.
On-board computers to control everything from engine efficiency to voiceactivated MP3/Bluetooth hands-free system.
Cashless catering system in school to add and subtract money from your account.
Self-service checkouts in supermarkets that scan, weigh, take payment and give change.
Contactless card payment systems where a small RFID (radio frequency ID) tag is embedded into the card and read when the card is near.
RFID technology – often used in library books and shops to detect theft, also has future applications in “smart” clothes and food products. Imagine the RFID tag in your clothes tells the washing machine how to wash them. Or a smart fridge that knows when the milk is past it’s sell-by date and adds it to your online shopping list.
Since we rely so much on technology there are huge problems when it goes wrong! If a supermarket checkout system goes down this could result in lost sales of thousands of pounds. However, if an automated system, like those onboard aircraft fails then it could end in disaster!
4 Why do we need to use the same professional standards when developing and maintaining computer systems? Without standards to adhere to we risk developing systems that are not compatible with each other. Would you be happy if your Nokia mobile could only call other Nokia mobiles? Standards also improve the quality of the computer system and its maintenance by ensuring that best practice is followed and people don’t cut corners. Considerations when creating computer systems: The Data Protection Act 1998 provides protection for all information stored on a computer system. It requires the person who owns the system to store the information securely and only use it for the purpose it was originally gathered for, e.g. the school holds data on you for the purpose of your education; it cannot sell this data to companies who may wish to sell you things.
The speed of progress means that many gadgets become old and obsolete quite quickly. This means there are potentially stockpiles of old technology which could end up in landfill. Many companies now recycle these by selling reconditioned devices to other countries or cannibalising the parts to be used again. Websites like Google use huge server-farms around the world. These buildings are full of computers running 24/7. There is an impact on the environment from the huge amount of electricity needed to run these server-farms.
Technology enables us to do many things....
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