Information and communication technologies (ICTs) systems now dominate our everyday lives. This unit will explain what constitutes such a system and how ICT systems work. You will also look at how ICT systems convey, store and manipulate data, and how they process data. Finally you will learn how these systems are used. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources from The Open University. Published in ePub 2.0.1 format, some feature such as audio, video and linked PDF are not supported by all ePub readers.