Computer systems would be of little real use without a method of input or output.
This chapter reviews how a number of input and output devices work. It also
considers a variety of applications which make use of these devices.
This textbook has been written to provide the knowledge, understanding and practical skills that a student would need for the Cambridge International Examinations Computer Science IGCSE and GCE O Level courses.
As you progress through this book you will begin to realise how complex computer
systems really are. By the time you reach Chapter 12 you should have a better
understanding of the fundamentals behind computers themselves and the software that
The HEXADECIMAL SYSTEM is very closely related to the binary system. Hexadecimal
(sometimes referred to as simply "hex") is a base 16 system and therefore needs to
use 16 different "values" to represent each digit.