This text is intended for students taking single semester units on computer systems, architecture and computer systems technology as part of an HND or undergraduate course. It describes and illustrates how the hardware and software components that go to make up the computer and its environment are organised and interconnected, thereby providing an efficient machine capable of carrying out an extensive range of tasks. The author takes a bottom-up approach, beginning with logic gates and data representation and culminating in an analysis of RISC processors and parallel architectures. Not more than a basic knowledge of computer programming is assumed. Throughout the text, self test questions are included; each chapter also contains exercises, a summary and suggestions for further reading.