Wicked Problems. Righteous Solutions

A Catalogue of Modern

Software Engineering Paradigms Peter DeGrace

and

Leslie Hulet Stahl

YOURDON PRESS P T R Prentice Hall Building

Upper Saddle River, NJ 07458

CONTENTS

INTRODUCTION 1

CHAPTER ONE—Software Engineering and Science 5

CHAPTER TWO—A Personal View of the "State of the Art" in Programming 11

Fads, Fashions, and Who We Are 21 Summary 25

CHAPTER THREE—The Waterfall Model 27 Beginning and Ending Points 29 Steps and Variations 32 Detailed Discussion 33

Initiation 33 Options Study (if there is one) 35 Requirements Gathering and Analysis Phase 37 Alternatives Study (if there is one) 42 Preliminary Design Phase 43 Detail Design Phase 46 Coding Phase 49 Module Test Phase 49 System Test (Verification) Phase 49 Installation and Delivery (Validation) Phase 51 Maintenance and Enhancement Phase 51

Closing Thoughts 53 Documentation 53 Reviews 56 A Word About Language 57

Summary 59

i

ii • Wicked Problems, Righteous Solutions

CHAPTER FOUR—Problems with the Waterfall Model 61 Incomplete Requirements 68 It Costs Too Much 70 It Takes Too Long 74 Variations 77 End-User Communications Gap 77 The "What" Separated from the "How" 80 Error Management 80 Wicked Problems 82 Final Thoughts and Summary 93

CHAPTER FIVE—Whirlpools, Incrementals, and Spirals.... 97 Attenuating and Truncating 104 Incrementals 112

CHAPTER SIX—Prototyping 119 How Prototyping is Used 126 When and Where Prototyping is Used 128

Prototyping Partially Replacing the Waterfall Model.... 131 Prototyping Fully Replacing the Waterfall Model 134

The Benefits of Using Prototyping 146 Problems With Prototyping 147 Some Closing Thoughts on the Hardware/Software Analogy 149

Reusability 151 Summary 151

CHAPTER SEVEN—The All-at-Once Model 153 Team Approaches—Sashimi and Scrum 154 The Two-Man Approach—Handcuffing 161 The One-Man Approach—Hacking 165 Summary 176

CHAPTER EIGHT—Other Models 177 Video Models 177

The Hollywood Model 177 The Outside-In Model 180 The Maintenance by Television (MTV) Model 182

The Cleanroom Model 183

Contents • iii

User Computing 189 System Engineering 192 Summary 201

CHAPTER NINE—Professionalism and Science 203 Professionalism 203

Deep but Narrow Knowledge 203 The Curse of the Power User 204 The Khomeini Effect (The True Believer) 206 Technical Decisions Made by Unqualified People 207

Science 214

BIBLIOGRAPHY 219