Understanding Microcomputers

175 Pages·1985·19.781 MB·English

by  Dennis Longley, Michael Shain (auth.)

UNDERSTANDING
MICROCOMPUTERS
UNDERSTANDING
MICROCOMPUTERS
Dennis Longley
and MichaeLShain
M
MACMILLAN PRESS
LONDON
MacmillanReferenceBooks
@The Macmillan Press Ltd, 1985
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). Any
person who does any unauthorised act in relation to this
publication may be liable to criminal prosecution and civil
claims for damages.
First published 1985 by
THE MACMILLAN PRESS LTD
London and Basingstoke
Associated companies in Auckland, Delhi, Dublin, Gaborone,
Hamburg, Harare, HongKong, Johannesburg, Kuala Lumpur,
Lagos, Manzini, Melbourne, Mexico City, Nairobi, New York,
Singapore, Tokyo.
British Library Cataloguing in Publication Data
Longley, Dennis
Understanding microcomputers.
1. Computer networks 2. Microcomputers
I. Title II. Shain, Michael
001.64'04 TK105.5
ISBN978-0-333-37573-0 ISBN 978-1-349-07553-9 (eBook)
DOI 10.1007/978-1-349-07553-9
The paperback edition of this book is sold subject to the
condition that it shall not, by way of trade or otherwise, be
lent, resold, hired out, or otherwise circulated without the
publisher's prior consent in any form of binding or cover other
than that in which it is published and without a similar
condition including this condition being imposed on the
subsequent purchaser
Contents
Preface xi
1 HOW MICROCOMPUTERS WORK
1.1 INTRODUCTION
1.2 THE MICROCOMPUTER SYSTEM
1.3 THE CLERKMODEL 2
1.4 THE PROGRAM 4
1.5 BLACK BOX MODEL 6
1.6 INPUT/OUTPUT 6
1.7 CAN IT MAKE A MISTAKE? 9
1.8 CONCLUSIONS 10
2 FILESAND RECORDS 11
2.1 INTRODUCTION 11
2.2 FILESAND RECORDS:AN OVERVIEW 11
2.3 FILESAND RECORDS: A DETAILED 14
ACCOUNT
2.3.1 Introduction 14
2.3.2 File processing 15
2.3.3 Housekeeping 17
3 MICROCOMPUTER HARDWARE 19
3.1 INTRODUCTION 19
3.2 MICROCOMPUTER HARDWARE: AN 20
OVERVIEW
3.2.1 Introduction 20
3.2.2 Microcomputer building blocks 22
3.3 MICROCOMPUTER HARDWARE: A 24
DETAILED ACCOUNT
3.3.1 Introduction 24
3.3.2 CPU 26
3.3.3 Memory 27
3.3.4 Buses and interfaces 28
4 MICROCOMPUTER PERIPHERALS 32
4.1 INTRODUCTION 32
4.2 CONVENTIONAL PERIPHERALS 33
4.2.1 Introduction 33
4.2.2 Keyboards 33
4.2.3 Video monitors and terminals 35
4.2.4 Backing storage 41
4.2.5 Printers 47
4.3 SPECIALAPPLICATIONS 53
4.3.1 Communications 53
4.3.2 Input devices 55
4.3.3 Output devices 61
4.4 CONCLUSIONS 63
5 MICROCOMPUTER SOFTWARE 64
5.1 INTRODUCTION 64
5.2 MICROCOMPUTERSOFTWARE: AN 64
OVERVIEW
6 OPERATING SYSTEMS 69
6.1 INTRODUCTION 69
6.2 OPERATINGSYSTEMS: AN OVERVIEW 70
6.2.1 The operations 70
6.2.2 Operating systems and application 72
programs
6.3 MS-DOS: A MICROCOMPUTER 72
OPERATING SYSTEM
6.3.1 Introduction 72
6.3.2 What is MS-DOS? 73
6.3.3 Getting started 74
6.3.4 Housekeeping 75
6.3.5 Copying and editing 78
6.3.6 User defined routines 81
6.3.7 Programs 82
vi
6.4 CONCLUSION 82
7 HIGH LEVEL LANGUAGES 83
7.1 INTRODUCTION 83
7.2 HIGH LEVELLANGUAGES: AN 83
OVERVIEW
7.2.1 Introduction 83
7.2.2 Translation 84
7.2.3 Typical languages 85
7.3 HIGH LEVELLANGUAGES: DETAILED 86
ACCOUNT
7.3.1 Introduction 86
7.3.2 Selecting the language 87
7.3.3 Programming in BASIC 87
7.3.4 An example of a BASIC program 94
7.3.5 Learning BASIC 95
8 LOW LEVEL LANGUAGES 97
8.1 INTRODUCTION 97
8.2 LOW LEVELLANGUAGES: AN 97
OVERVIEW
8.2.1 Introduction 97
8.3 MACHINE CODEAND ASSEMBLY 98
LANGUAGE
8.3.1 Introduction 98
8.3.2 Data transfer instructions 100
8.3.3 Arithmetic instructions 101
8.3.4 Control transfer instructions 102
8.3.5 Subroutines 105
8.4 ASSEMBLING AND TESTING 105
9 COMPILERS, INTERPRETERSAND 107
ASSEMBLERS
9.1 Introduction 107
9.2 AN OVERVIEW 108
9.2.1 Interpreters 108
9.2.2 Compilers 110
9.2.3 Assemblers 110
vii
9.3 A DETAILEDACCOUNT 110
9.3.1 Introduction 110
9.3.2 Interpreters 111
9.3.3 Compilers 112
9.3.4 Assemblers 114
10 WRITING YOUR OWN APPLICATIONS 115
10.1 INTRODUCTION 115
10.2 WRITING YOUR OWN APPLICATION:AN 116
OVERVIEW
10.3 WRITING YOUR OWN APPLICATIONS: 117
DETAILEDACCOUNT
10.3.1 Introduction 117
10.3.2 Defining the problem in outline 117
10.3.3 Seeking available software packages and 118
estimating computing costs
10.3.4 Defining the problem in detail 120
10.3.5 Selecting the language 121
10.3.6 Estimating the system requirement 122
10.3.7 Specifying file formats, data input and 124
output formats, operator actions
10.3.8 Programming 126
10.3.9 Debugging 126
10.3.10 Testing 128
10.3.11 Setting up the system 128
10.3.12 Trial running 129
10.3.13 Documentation 130
10.3.14 Conclusion 131
11 SELECTING A PACKAGE 132
11.1 INTRODUCTION 132
11.2 SOFTWARECAPABILITIES 132
11.3 HARDWARE COMPATIBILITY 133
11.4 PACKAGEPERFORMANCE 134
11.5 DOCUMENTATION 136
11.6 BUYING A PACKAGE 136
11.7 CONCLUSIONS 138
viii
12 AN INTEGRATEDSPREADSHEET 139
PACKAGE
12.1 INTRODUCTION 139
12.2 SPREADSHEET 140
12.3 GRAPHICS 142
12.4 DATABASE 143
12.5 PROGRAMMING 143
12.6 CONCLUSIONS 144
GLOSSARY 146
ix
PREFACE
The contents of this book are derived from the Understanding
Microcomputers section of the Microcomputer Users Handbook
by Longley and Shain. It is written primarily for the business
microcomputer user who may wish to obtain an overall view
of the topic in one reading or to dip into particular sections to
uncover the meaning behind a particular piece of jargon.
The development of microcomputers over the past decade
commenced with video games, moved through hobbyist
computers with audio cassette players and quickly established
an entirely new market in business computer systems. The
success of the microcomputer market, coupled with the rapid
developments in microelectronics and software, has resulted
in the development of small businesscomputing systems which
rival the powerof earlydata processing mainframe installations.
The business microcomputer has revolutionized the data
processingindustry; small businesses and professional users
have computerized their operations whilst large companies
have completely restructured their data processing operations.
The computing industry is now poised to enter the fifth
generation era in which computers will exploit the potential of
artificial intelligence and herald in the powerful user-friendly
executive workstation.
The successful exploitation of computers has always
depended upon the optimum combination of human and
computer resources. In the business world the user should
undertake a fundamental reappraisal of his modus operandi
inthe light of the facilities offered by the computer system.
Ideally the businessman would be able to exploit the power of
the business system with a minimal knowledge of the internal
hardware and software functions. However, the ultimate user
friendly computer system is still a goal for the future rather
than a current reality.
The computer user who holds his system at arms length,
relegating its role to a particular operation, is unlikely to obtain
the maximum benefit from its full potential. Moreover the
microcomputer market continues to produce new hardware
components, peripherals and software which can substantially
improve the performance of the basic system. The selection of
the worthwhile enhancements, from the myriad on offer,
demands some degree of familiarity with the system.
On the other hand any attempt to develop a mastery of
computing opens up a Pandora's Box of technology and
jargon. The problem for the average user is to predetermine
the relevance and the necessary depth of knowledge in the
various aspects of hardware and software.
This book addresses itself to the problem of the average
business microcomputer user. In each chapter the reader is
xi