Reliability in Computer System Design
Edition
Dr. Dhillon is a full professor in the Faculty of Science and Engineering, University of Ottawa.
He attended the University of Wales where he received a B.Sc. in Electrical and Electronic Engineering and a M.Sc. in Industrial and Systems Engineering. His Ph.D. in Reliability Engineering was received from the University of Windsor. He wrote his doctoral thesis on reliability evaluation of networks composed of three state devices. He is Advisory Editor of "Microelectronics and Reliability: An International Journal", Associate Editor of "International Journal of Energy Systems", and Editor-at-Large for Engineering Books (Marcel Dekker, Inc.). Dr. Dhillon served as an associate editor of the 10-13th Annual Modeling and Simulation Proceedings, Pittsburgh, Pennsylvania, USA. He has published over 170 articles on Reliability Engineering as well as nine books on various aspects of Engineering Reliability and related areas. Three of his books are translated into Russian and Chinese.
Serving as a referee to many national and international journals, book publishers and other bodies, he has presented keynote and invited lectures at various national and international conferences. Dr. Dhillon has several years of experience in electronics and nuclear power industries.
He is recipient of the American Society for Quality Control's Austin J. Bonis Reliability Award and the Society of Reliability Engineers' Merit Award, as well as several appreciation certificates from various American professional societies. A registered Professional Engineering in Ontario, Professor Dhillon is listed in the American Men and Women of Science, Dictionary of International Biography, Men of Achievement, Who's Who in Technology, Personalities of America, etc.
BIOGRAPHY OF THE AUTHOR xi
PREFACE xii
1. INTRODUCTION 1
1.1 Need for Reliability 1
1.2 History of Computer System Reliability 1
1.2.1 Software Reliability 2
1.3 Terms and Definitions 3
1.4 Scope of the Text 4
1.5 Summary 4
1.6 Exercises 5
1.7 References 5
2. BASIC RELIABILITY MATHEMATICS 9
FOR COMPUTER SYSTEMS
2.1 Introduction 9
2.2 Probability 9
2.2.1 Properties of Probability 10
2.3 Probability Distributions 11
2.3.1 Continuous Distributions 11
2.3.2 Discrete Distributions 15
2.4 Laplace Transforms 17
2.5 Final Value Theorem 19
2.6 Markov Modeling 21
2.7 The Method of Maximum Likelihood 23
2.8 Summary 25
2.9 Exercises 25
2.10 References 26
3. INTRODUCTION TO QUALITY CONTROL
AND RELIABILITY 27
3.1 Introduction 27
3.2 Quality Control 27
3.2.1 Acceptance Sampling 28
3.2.2 Inspection Related Formulas 28
3.2.3 Control Charts 30
3.2.4 Activities of a Quality Control Department 30
3.3 Basic Reliability Concepts 31
3.3.1 General Reliability Function 31
3.3.2 Failure Rate Models for Parts and Equipment 35
3.3.3 Reliability Configurations 36
3.3.4 Fault Trees 47
3.4 Comparative Reliability Analysis of Simplex and 51
Redundant Systems
3.4.1 Analysis 52
3.4.2 Time-Dependent Analysis 59
3.5 Reliability Analysis of a Triple-Modular Redundant 62
System with Repair
3.6 Summary 68
3.7 Exercises 68
3.8 References 69
4. COMPUTER FAILURES 71
4.1 Introduction 71
4.2 Causes of Computer Failures 71
4.3 Computer System Error Recovery Philosophies 72
4.4 Peripheral Device Errors 75
4.5 Computer Software Failures 75
4.5.1 Selected Definitions 76
4.5.2 Failure Modes of the Software System 76
4.5.3 Classification of Errors in Programming 78
4.5.4 Human Errors in Software Development 79
4.5.5 Software Error Cost Analysis 82
4.6 Software and Hardware Reliability 83
4.7 Summary 84
4.8 Exercises 85
4.9 References 86
5. INTRODUCTION TO COMPUTER SYSTEM 87
RELIABILITY MODELING
5.1 Introduction 87
5.2 Issues in Computer System Reliability 87
5.3 Redundant Computer Systems 88
5.4 Reliability Measures for Computers 88
5.5 Formulas for System Availability and 89
Computing Efficiency
5.6 Markov Modeling of Computer Associated Systems 90
5.6.1 Model I 90
5.6.2 Model II 93
5.6.3 Model III 97
5.7 Reliability Analysis of a Redundant System 99
5.8 Summary 100
5.9 Exercises 101
5.10 References 101
6. RELIABILITY ANALYSIS OF COMPUTER SYSTEMS 103
6.1 Introduction 103
6.2 Redundancy Schemes for Computer Systems 103
6.2.1 Scheme Type I 103
6.2.2 Scheme Type II 104
6.2.3 Scheme Type III 104
6.2.4 Scheme Type IV 106
6.2.5 Scheme Type V 107
6.2.6 Scheme Type VI 111
6.3 Reliability Evaluation of a Multi-Mini- 115
Processor Computer
6.4 Reliability Analysis of Repairable Systems 115
6.4.1 Model I 116
6.4.2 Model II 118
6.5 Reliability Evaluation of a Computer System 120
6.6 Summary 126
6.7 Exercises 127
6.8 References 127
7. MICROCOMPUTER SYSTEM RELIABILITY ANALYSIS 129
AND QUEUING THEORY
7.1 Introduction 129
7.2 Microcomputers 130
7.2.1 Microcomputers and Related Products 130
7.2.2 Reliability Analysis of Microcomputer Systems 131
with Triple-Modular Redundancy
7.3 Queuing Theory 135
7.3.1 Important Laws and Formulas 135
7.3.2 Selective Queuing Theory Models 139
7.4 Summary 145
7.5 Exercises 146
7.6 References 146
8. ADDITIONAL TOPICS IN COMPUTER 149
HARDWARE RELIABILITY
8.1 Introduction 149
8.2 Reliability Analysis of Computer Systems with 150
Common-Cause Failures
8.3 Computer System Life Cycle Costing 156
8.4 Integrated Circuit Defects 159
8.5 Reliability Analysis of Space Computers 160
8.6 Computer Memory Reliability Modeling 163
8.7 Summary 165
8.8 Exercises 165
8.9 References 166
9. SOFTWARE QUALITY MANAGEMENT 167
9.1 Introduction 167
9.2 The Software Quality Assurance Program 167
9.2.1 Functions of Software Quality Assurance 168
9.2.2 Ten Components of a Successful Software Quality 171
Assurance Program
9.2.3 Software Design Reviews and Reasons for High 172
Software Cost
9.2.4 Factors Responsible for the Software 173
Development Problem
9.3 Software Quality Assurance Organization 173
9.3.1 Responsibilities and Qualifications of a 173
Software Quality Assurance Manager
9.3.2 Attributes of a Good Software Quality 174
Assurance Engineer
9.4 Software Configuration Management 175
9.4.1 Advantages of Software Configuration Management 176
9.5 Software Quality Assurance Standards 176
9.6 Software Quality Assurance Benefits 177
9.7 Summary 178
9.8 Exercises 178
9.9 References 179
10. SOFTWARE DESIGN AND TESTING 181
10.1 Introduction 181
10.2 Software Life Cycle 181
10.3 Tools of the Programming Trade 183
10.3.1 Development Tools 183
10.3.2 Test and Evaluation Tools 183
10.3.3 Operations and Maintenance Tools 184
10.4 Software Design Methods 184
10.4.1 Design Quality Measures 185
10.4.2 Design Representation Tools 186
10.4.3 Design Techniques 186
10.5 Software Testing 189
10.5.1 Elements of a Good Test Plan 190
10.5.2 Characteristics of a Simple and Super Complex 190
Programs
10.5.3 Types of Testing 191
10.5.4 Program Automated Testing Tools 193
10.6 Software Problem Symptoms and Causes 194
10.7 Summary 195
10.8 Exercises 196
10.9 References 196
11. SOFTWARE RELIABILITY MODELING 199
11.1 Introduction 199
11.2 A Brief History of Software Reliability Models 199
11.3 Classification of Software Reliability Models 201
11.4 Software Reliability Models 202
11.4.1 Model I 202
11.4.2 Model II 204
11.4.3 Model III 207
11.4.4 Model IV 209
11.4.5 Model V 211
11.4.6 Model VI 212
11.5 Summary 214
11.6 Exercises 215
11.7 References 215
12. SOFTWARE MODELS 217
12.1 Introduction 217
12.2 Selected Mathematical Models 217
12.2.1 Model I 217
12.2.2 Model II 218
12.2.3 Model III 219
12.2.4 Model IV 220
12.2.5 Model V 220
12.2.6 Model VI 221
12.2.7 Model VII 223
12.2.8 Model VIII 223
12.2.9 Model IX 224
12.2.10 Model X 225
12.2.11 Model XI 227
12.2.12 Model XII 227
12.2.13 Model XIII 228
12.2.14 Model XIV 229
12.2.15 Model XV 229
12.2.16 Model XVI 230
12.3 Summary 230
12.4 Exercises 231
12.5 References 232
APPENDIX 233
A.1 Introduction 233
A.2 Computer Hardware Reliability 233
A.3 Computer Software Reliability 253
AUTHOR INDEX 275
SUBJECT INDEX 279