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MASTERING COMPUTERS MACMILLAN MASTER SERIES Banking Basic English Law Basic Management Biology British Politics Business Communication Business Microcomputing Catering Science Chemistry COBOL Programming Commerce Computer Programming Computers Data Processing Economic and Social History Economics Electrical Engineering Electronics English Grammar English Language English literature Financial Accounting French French 2 German Hairdressing Italian Japanese Keyboarding Marketing Mathematics Modern British History Modern European History Modern World History Nutrition Office Practice Pascal Programming Physics Practical Writing Principles of Accounts Social Welfare Sociology Spanish Spanish 2 Statistics Statistics with your Microcomputer Study Skills Typewriting Skills Word Processing MASTERING COMPUTERS THIRD EDITION GRAHAM WRIGHT M MACMILLAN EDUCATION Text and tables © G. G. L. Wright 1982, 1984, 1988 Illustrations © Macmillan Education 1982, 1984, 1988 All rights reserved. No reproduction, copy or transmission of this publication may be made without written permission. No paragraph of this publication may be reproduced, copied or transmitted save with written permission or in accordance with the provisions of the Copyright Act 1956 (as amended), or under the terms of any licence permitting limited copying issued by the Copyright Licensing Agency, 33-4 Alfred Place, London WC1E 7DP. Any person who does any unauthorised act in relation to this publication may be liable to criminal prosecution and civil claims for damages. First edition 1982 Reprinted 1982 (3 times), 1983 (twice) Second edition 1984 Third edition 1988 Published by MACMILLAN EDUCATION LTD Houndmills, Basingstoke, Hampshire RG21 2XS and London Companies and representatives throughout the world Typeset by TecSet Ltd, Wallington, Surrey ISBN 978-0-333-45640-8 ISBN 978-1-349-09944-3 (eBook) DOI 10.1007/978-1-349-09944-3 ISBN 978-0-333-45641-5 Pbk export v CONTENTS vii List of figures Acknowledgements Preface to the third edition Introduction 1 Introducing the computer X xi xiii 1.1 What is a computer? 1.2 The computer as an information processor 1.3 Computers today 1.4 Computers, travel and leisure Computers in numerical computation Computers in data processing Computers in control Personal computing Information systems and information technology 2.6 Computers and travel 2 The who, what, and why of 2.1 computers 2.2 2.3 2.4 2.5 3 How the computer works 3 .1 Data representation 3.2 The processor and programs 3.3 Internal storage 4 Peripherals and the computer 4.1 4.2 4.3 4.4 4.5 S Systems analysis - putting the computer to work 6 Data and records Backing storage Input/output devices Terminals Data transmission Using computers in the travel trade 5.1 Deciding what you want the computer to do 5.2 Acquiring a packaged system 5.3 Designing bespoke software 5.4 Making a system work 5.5 System documentation 5 .6 Designing computer systems for the travel trade 6.1 Data analysis 6.2 Data structure 6.3 Records and record access 1 2 9 21 28 31 34 37 41 44 49 57 65 74 88 113 117 123 130 135 141 143 146 151 161 164 166 CONTENTS 6.4 6.5 6.6 6.7 Records and files Records and databases Protecting data Data in a travel system 172 177 182 184 7 Programming a computer 7 .1 7.2 7.3 7.4 7.5 7.6 7. 7 7.8 The programming task The program specification Program design Effective programming Coding Program testing Program documentation Programming a travel system 190 192 192 198 199 210 213 214 8 Acquiring computer hardware 8.1 Sources of hardware 8.2 Financing hardware- purchase, rental and leas