THIRD EDITION

THE ART OF SYSTEMS

ARCHITECTING

MARK W. MAIER EBERHARDT RECHTIN

C\ CRC Press Taylor & Francis Group Boca Raton London New York

CRC Press is an imprint of the Taylor & Francis Group, an in form a business

Contents Preface xv

Part I: Introduction A Brief Review of Classical Architecting Methods 1 Notes 4

Chapter 1 Extending the Architecting Paradigm 5 Introduction: The Classical Architecting Paradigm 5 Responding to Complexity 5 The High Rate of Advances in the Computer and Information Sciences... 7 The Foundations of Modern Systems Architecting 8 The Architecture Paradigm Summarized 19 The Waterfall Model of Systems Acquisition 20 Spirals, Increments, and Collaborative Assembly 23 Scopes of Architecting 25 Conclusion 27 Notes and References 27

Chapter 2 Heuristics as Tools 29 Introduction: A Metaphor 29 Heuristics as Abstractions of Experience 30 Selecting a Personal Kit of Heuristic Tools 31 Using Heuristics 34 A Process Framework for Architecting Heuristics 35 Heuristics on Heuristics 38 A Taxonomy of Heuristics 39 New Directions 41 Conclusion 41 Notes and References 42

viii Contents

Part II: New Domains, New Insights

Case Study 1: DC-3 47 The History 47 Architecture Interpretation 51 Three Story Variations 51 Was the Boeing 247 Successfully Architected? 52 What Is the "Architecture" of the DC-3? 53 Art Raymond's Principles 53 Notes and References 55

Chapter 3 Builder-Architected Systems 57 Introduction: The Form-First Paradigm 57 Technological Substitutions within Existing Systems 59 Consequences of Uncertainty of End Purpose 61 Architecture and Competition 61 Reducing the Risks of Uncertainty of End Purpose 63 Risk Management by Intermediate Goals 64 The "What Next?" Quandary 65 Controlling the Critical Features of the Architecture 66 Abandonment of an Obsolete Architecture 67 Creating Innovative Teams 68 Architecting "Revolutionary" Systems 70 Systems Architecting and Basic Research 72 Heuristics for Architecting Technology-Driven Systems 73 Conclusion 74 Exercises 74 Notes and References 75

Case Study 2: Mass and Lean Production 77 Introduction 77 An Architectural History of Mass Production 77 Cottage Industry (1890s to 1910s) 78 Birth of Mass Production (1908-1913) 78 Competition from New Quarters (1920s to 1930s) 79 The Toyota Production System (1940s to 1980s) 80 Metaphor or Vision Changes 81 Craftsmen 81 A Car for the Masses, or If We Build It, It Will Sell 81 Cars as Fashion 82 The Supermarket Metaphor 82 The Toyota Way 82 Elements of the Architecture of the Ford Production System 82 The Assembly Line 83

Contents ix

Enterprise Distribution 83 Management Processes 84 Quality Assurance for Distributed Production 84 Devotion to Component-Level Simplification 84 Social Contract 85 Conclusion 85 Notes and References 86

Chapter 4 Manufacturing Systems 87 Introduction: The Manufacturing Domain 87 Manufacturing in Context 88 Architectural Innovations in Manufacturing 91 Dynamic Manufacturing Systems 93 Lean Production 105 Flexible Manufacturing 108 Heuristics for Architecting Manufacturing Systems I l l Conclusion I l l Exercises 112 Notes and References 112

Case Study 3: Intelligent Transportation Systems 115 Introduction 115 ITS Concepts 116 ITS Sociotechnical Issues 118 Who Is the Client for an Architect? 118 Public or Private? 119 Facts and Perceptions 121 Architecture as Shared Invariants 122 Dominance of Economics 122 Notes and References 123

Chapter 5 Social Systems 125 Introduction: Defining Sociotechnical Systems 125 Public Participation 125 The Foundations of Sociotechnical Systems Architecting 127 The Separation of Client and User 127 Socioeconomic Insights 128 The Interaction between the Public and Private Sectors 130 Facts versus Perceptions: An Added Tension 131 Heuristics for Social Systems 134 Conclusion 135 Exercises 135 Notes and References 136

x Contents

Case Study 4: Hierarchical to Layered Systems 137 Business Background 137 Motivation for Change 138 The Layered Alternative 140 The Pain of the Transition 142 Results 144

Chapter 6 Software and Information Technology Systems 147 Introduction: The Status of Software Architecting 147 Software as a System Component 151 Systems, Software, and Process Models 153 The Problem of Hierarchy 161 The Role of Architecture in Software-Centered Systems 166 Programming Languages, Models, and Expression 167 Architectures, "Unifying" Models, and Visions 169 Directions in Software Architecting 170 Exercises 178 Notes and References 179

Case Study 5: The Global Positioning System 181 The History 181 The Origins of GPS: The Foundational Programs 181 Inertial Navigation and Its Limits 182 Weapon Delivery 182 The Transit Program 182 TIMATION 183 621B 184 The Origin of GPS 184 Parkinson and Currie 185 The Fateful Weekend 185 The Long Road to Revolution 186 The Timeline to Operation 186 Commercial Markets and the Gulf War 187 Revolution in the Second Generation 187 Ubiquitous GPS 188 GPS-Guided Weapons 188 Architecture Interpretation 189 Right Idea, Right Time, Right People 189 Be Technically Aggressive, But Not Suicidal 190 Consensus without Compromise 191 Architecture as Invariants 192 Revolution through Coupled Change 192 Conclusion 193 Notes and References 194

Contents xi

Chapter 7 Collaborative Systems 195 Introduction: Collaboration as a Category 195 Collaborative System Examples 197 Analogies for Architecting Collaborative Systems 202 Collaborative System Heuristics 203 Variations on the Collaborative Theme 207 Misclassification 208 Standards and Collaborative Systems 211 Conclusion 213 Exercises 214 Exercises to Close Part II 214 Notes and References 215

Part III: Models and Modeling Introduction to Part III 217 A Civil Architecture Analogy 217 Guide to Part III 218

Chapter 8 Representation Models and Systems Architecting 221 Introduction: Roles, Views, and Models 221 Roles of Models 222 Models, Viewpoints, and Views 223 Classification of Models by View 225 Conclusion 243 Exercises 245 Notes and References 245

Chapter 9 Design Progression in Systems Architecting 247 Introduction: Architecting Process Components 247 Design Progression 248 Introduction by Examples 249 Design as the Evolution of Models 250 Evaluation Criteria and Heuristic Refinement 250 Design Concepts for Systems Architecture 254 Architecture and Design Disciplines 277 Conclusion 282 Exercises 282 Notes and References 283

Chapter 10 Integrated Modeling Methodologies 285 Introduction 285 General Integrated Models 286 Integrated Modeling and Software 292

xü Contents

Integrated Models for Manufacturing Systems 307 Integrated Models for Sociotechnical Systems 308 Conclusion 309 Exercises 310 Notes and References 310

Chapter 11 Architecture Frameworks 313 Introduction 313 Defining an Architecture Framework 314 Current Architecture Frameworks 315 Research Directions 327 Adapting Processes to Frameworks 329 Conclusion 333 Notes and References 333

Part IV: The Systems Architecting Profession

Chapter 12 Architecting in Business and Government 339 Problem-System-Program-Organization 339 Strategy and Architecture in Business and Government 343 Architecture of Programs 346 Strategic Architecting of Programs 350 Enterprise Architecture 353 Conclusion 359 Notes and References 359

Chapter 13 The Political Process and Systems Architecting 361 Brenda Forman

Introduction: The Political Challenge 361 Politics as a Design Factor 362 The First Skill to Master 364 Heuristics in the Political Process: "The Facts of Life" 365 A Few More Skills to Master 373 Conclusion 373

Chapter 14 The Professionalization of Systems Architecting 375 Elliott Axelband

Introduction 375 The Profession of Systems Engineering 375 Systems Architecting and Systems Standards 378 The Origins of Systems Standards 379 Commercial Standards 382 Company Standards 384

Contents xiii

A Summary of Standards Developments, 1950-1995 385 Systems Architecting Graduate Education 386 Curriculum Design 387 Advanced Study in Systems Architecting 389 Professional Societies and Publications 389 Conclusion: An Assessment of the Profession 390 Notes and References 391

Appendix A: Heuristics for Systems-Level Architecting 395 Introduction: Organizing the List 395 Heuristic Tool List 397 Exercises 407 Notes and References 407

Appendix B: Reference Texts Suggested for Institutional Libraries...409 Architecting Background 409 Management 409 Modeling 410 Specialty Areas 410 Software 410 Systems Sciences 411 Systems Thinking 411

Appendix C: On Defining Architecture and Other Terms 413 Defining "Architecture" 413 Models, Viewpoints, and Views 420 Reference 422

Glossary 423

Author Index 427

Subject Index 431