Software Design for Real-time Systems

521 Pages·1991·13.148 MB·English

by  J. E. Cooling (auth.)

Software
Design
for
Real-time
Systems
Software
Design
for
Real-time
Systems
J.E. COOLING
Department of Electronic and Electrical Engineering.
University of Technology. Loughborough
SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
First published 1991
©J. E.Cooling 1991
Originally published by Chapman and Hall in 1991
Softcover reprint of the hardcover I st edition 1991
Typeset in 10/12 Sabon by Selectmove Limited, London
ISBN 978-0-442-31174-2 ISBN 978-1-4899-2957-0 (eBook)
DOI 10.1007/978-1-4899-2957-0
0442311745 (USA)
All rights reserved. No part of this publication may be reproduced
or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, or stored in any
retrieval system of any nature, without the written permission of the
copyright holder and the publisher, application for which shall be made
to the publisher.
British Library Cataloguing in Publication Data
Cooling, J. E. (Jim E)
Software design for real-time systems.
1. Real time computer systems. Software. Design
1. Title
005.12
ISBN 978-0-442-31174-2
Library of Congress Cataloging-in-Publication Data
available
To Nieve and Niall
Le gni agus gach dea-ghui
Contents
Acknowledgements xi
Preface X11l
Glossary XVI
1 Real-time systems - setting the scene 1
1.1 Categorizing computer systems 2
1.2 Real-time computer systems 4
1.3 The computing elements of real-time systems 13
1.4 Software for real-time applications - some general comments 26
References 27
2 The search for dependable software 29
2.1 What do we want in our software? 29
2.2 Software errors 32
2.3 The basics of good software 43
References 49
3 First steps - requirements analysis and specification 51
3.1 The software life cycle 52
3.2 The importance of the requirements stages 58
3.3 Making mistakes - sources and causes 60
3.4 A practical approach to analysis and specification 66
3.5 Communication aspects - the role of prototyping 78
3.6 Final comments 87
References 87
Further reading 88
4 Program design concepts 89
4.1 Design fundamentals 90
4.2 The elements of modular design 99
viii Contents
4.3 Program control structures - the influence of structured
programmmg 115
4.4 Functional structuring of software designs 121
4.5 Object-structured (oriented) design 127
4.6 Data structured design 139
4.7 Building the software - alternative techniques 140
4.8 A last comment 142
References 142
Further reading 144
5 Diagramming - an introduction 145
5.1 Diagrams - why? 145
5.2 The essentials of software diagrams 153
5.3 Practical diagramming techniques - a general comment 164
References 164
6 Diagramming methodologies in software design 165
6.1 Introduction 165
6.2 Context and entity relationship diagrams 166
6.3 Data flow diagrams 168
6.4 Process-structure diagrams 170
6.5 Program-structure diagrams 170
6.6 Event-dependent diagrams 185
6.7 Structured text 190
6.8 Data structure diagrams 192
6.9 Producing diagrams 193
6.10 A last comment 193
References 195
Further reading 196
7 Formal specification methods 197
7.1 Formal methods - are they useful? 197
7.2 The specification problem - again 198
7.3 Why mathematics? 199
7.4 Formal methods - general concepts 202
7.5 VDM
by P. Robinson, Rolls-Royce and Associates Ltd 204
7.6 Z
by M. Bushel 213
7.7 Final comments 221
References 221
Further reading 222
Contents ix
8 Languages for real-time systems 223
8.1 Choosing a programming language - the real questions 224
8.2 High-level languages - requirements 226
8.3 Program syntax and layout rules - the readability factor 227
804 Program design and compilation methods 230
8.5 Variable usage - scope, visibility, lifetime and declaration 234
8.6 Data types - concepts and uses 236
8.7 Program flow control 249
8.8 Interfacing to other languages 254
8.9 Exception handling 255
8.10 Accessing processor hardware -low-level facilities 256
8.11 Miscellaneous items 260
8.12 Languages for real-time systems - survey 261
8.13 A comparison of Ada, C, and Modula-2/Pascal 268
8.14 Assembly language programming 279
8.15 A closing comment 282
References 283
Further reading 284
9 Operating systems for real-time applications 285
9.1 Why use an operating system? 285
9.2 Basic features of real-time operating systems 287
9.3 Scheduling - concepts 291
904 Scheduling - implementation 297
9.5 Control of shared resources - mutual exclusion 303
9.6 Intertask communication 318
9.7 Memory management 323
9.8 Standard executives - software in silicon 324
9.9 Closing comments 326
References 328
10 Software analysis and design - methods, methodologies and tools 329
10.1 The development process 330
10.2 Controlled requirements expression - CORE 331
10.3 Yourdon Structured Method - YSM 344
lOA Jackson System Development - JSD 358
10.5 MASCOT 372
10.6 HOOD - hierarchical object-oriented design 387
10.7 Software tools - an overview 398
10.8 A last review 402
References 403
Further reading 403
x Contents
11 Development tools 404
11.1 The development process 404
11.2 Software debugging - an overview 411
11.3 Software debugging on the host 415
11.4 Software debugging in the target - software-based techniques 434
11.5 Software debugging in the target - hardware-based methods 441
11.6 Debugging in host/target combinations 451
11.7 Performance analysis tools 455
11.8 Installing code into the target - non-volatile software (firmware) 460
11.9 Final comments 464
References 465
12 Documentation and testing 467
12.1 Documentation - what and why? 467
12.2 Software life-cycle documentation - overview 474
12.3 System functional specifications 475
12.4 Software structure specifications 478
12.5 Source code listings 481
12.6 Software testing - methods and documentation 481
12.7 Configuration and version control 489
12.8 Reading material - references, bibliography and general guidance 490
Index 493
Acknowledgements
CONTRIBUTORS
Paul Robinson (Rolls-Royce and Associates Ltd) and Mike Bushell: for making
the formal methods chapter readable, interesting and understandable. This
book would have been a much lesser text without their contributions.
Janet Redman: for producing such a good set of diagrams, on time, as specified,
and with good humour.
ADVICE AND ASSISTANCE
Steve Mallon (British Aerospace Dynamics pIc): who gave so much time and
effort for the development of the CORE and MASCOT examples.
Len Griffiths (British Aerospace Dynamics pIc): for generously providing the
CORE and MASCOT tool facilities.
Bill Smith (British Aerospace Dynamics pIc): for his patience and time in
showing how MASCOT 3 is handled by professionals.
Richard Kaiser and Phil Sulley (Yourdon International Ltd.): for the time and
assistance to develop the YSM examples.
John Cameron (Michael Jackson Systems Ltd.): for his help in the JSD work.
Stuart Frost (ISS Ltd.): for his time and effort in the development of the HOOD
example.
Pamela Webster (RPM Systems): for her enthusiastic and informative efforts in
producing diagrams for the AT RON debugger text.
And to many others who helped along the way by providing comments,
technical information, photos, etc.
CRITICS AND ASSESSORS
My good friend Alan Cuff: for encouragement, support and incisive (if
sometimes occasional) proofreading.
Niall and Jo: for taking the time to wade through the draft manuscript, and for
their many useful and fresh ideas.
Two anonymous reviewers: for their highly detailed, painstaking and extensive
review effort. It has been much appreciated.