Jean-Louis Boulanger is currently an Independent Safety Assessor (ISA) in the railway sector focusing on software elements. He is a specialist in the field of software engineering (requirement engineering, semi-formal and formal method, proof and model-checking). He also works as an expert for the French notified body CERTIFER in the field of certification of safety critical railway applications based on software (ERTMS, SCADA, automatic subway etc.). His research interests include requirements, software verification and validation, traceability and RAMS with a special focus on SAFETY.

• INTRODUCTION ixCHAPTER 1. SAFETY MANAGEMENT 11.1. Introduction 11.2. Dependability 11.3. Conclusion 81.4. Bibliography 8CHAPTER 2. FROM SYSTEM TO SOFTWARE 92.1. Introduction 92.2. Systems of command and control 102.3 System 132.4 Software implementation 142.5. Conclusion 162.6. Bibliography 172.7. Glossary 17CHAPTER 3. CERTIFIABLE SYSTEMS 193.1. Introduction 193.2. Normative context 203.3. Conclusion 373.4. Bibliography 383.5. Glossary 41CHAPTER 4. RISK AND SAFETY LEVELS 434.1. Introduction 434.2. Basic definitions 434.3. Safety implementation 484.4. In standards IEC 61508 and IEC 61511 704.5. Conclusions 744.6. Bibliography 744.7. Acronyms 77CHAPTER 5. PRINCIPLES OF HARDWARE SAFETY 795.1. Introduction 795.2. Safe and/or available hardware 795.3. Reset of a processing unit 805.4. Presentation of safety control techniques 815.5. Conclusion 1175.6. Bibliography 1185.7. Glossary 119CHAPTER 6. PRINCIPLES OF SOFTWARE SAFETY 1216.1. Introduction 1216.2. Techniques to make software application safe 1216.3. Other forms of diversification 1496.4. Overall summary 1506.5. Quality management 1506.6. Conclusion 1556.7. Bibliography 1566.8. Glossary 157CHAPTER 7. CERTIFICATION 1597.1. Introduction 1597.2. Independent assessment 1597.3. Certification 1607.4. Certification in the rail sector 1617.5. Automatic systems 1717.6. Aircraft 1717.7. Nuclear 1717.8. Automotive 1727.9. Spacecraft 1727.10 Safety case 1727.11 Conclusion 1737.12 Bibliography 1747.13 Glossary 176CONCLUSION 177INDEX  179

Jean-Louis Boulanger is currently an Independent Safety Assessor (ISA) in the railway sector focusing on software elements. He is a specialist in the field of software engineering (requirement engineering, semi-formal and formal method, proof and model-checking). He also works as an expert for the French notified body CERTIFER in the field of certification of safety critical railway applications based on software (ERTMS, SCADA, automatic subway etc.). His research interests include requirements, software verification and validation, traceability and RAMS with a special focus on SAFETY.

• INTRODUCTION ixCHAPTER 1. SAFETY MANAGEMENT 11.1. Introduction 11.2. Dependability 11.3. Conclusion 81.4. Bibliography 8CHAPTER 2. FROM SYSTEM TO SOFTWARE 92.1. Introduction 92.2. Systems of command and control 102.3 System 132.4 Software implementation 142.5. Conclusion 162.6. Bibliography 172.7. Glossary 17CHAPTER 3. CERTIFIABLE SYSTEMS 193.1. Introduction 193.2. Normative context 203.3. Conclusion 373.4. Bibliography 383.5. Glossary 41CHAPTER 4. RISK AND SAFETY LEVELS 434.1. Introduction 434.2. Basic definitions 434.3. Safety implementation 484.4. In standards IEC 61508 and IEC 61511 704.5. Conclusions 744.6. Bibliography 744.7. Acronyms 77CHAPTER 5. PRINCIPLES OF HARDWARE SAFETY 795.1. Introduction 795.2. Safe and/or available hardware 795.3. Reset of a processing unit 805.4. Presentation of safety control techniques 815.5. Conclusion 1175.6. Bibliography 1185.7. Glossary 119CHAPTER 6. PRINCIPLES OF SOFTWARE SAFETY 1216.1. Introduction 1216.2. Techniques to make software application safe 1216.3. Other forms of diversification 1496.4. Overall summary 1506.5. Quality management 1506.6. Conclusion 1556.7. Bibliography 1566.8. Glossary 157CHAPTER 7. CERTIFICATION 1597.1. Introduction 1597.2. Independent assessment 1597.3. Certification 1607.4. Certification in the rail sector 1617.5. Automatic systems 1717.6. Aircraft 1717.7. Nuclear 1717.8. Automotive 1727.9. Spacecraft 1727.10 Safety case 1727.11 Conclusion 1737.12 Bibliography 1747.13 Glossary 176CONCLUSION 177INDEX  179

Jean-Louis Boulanger is currently an Independent Safety Assessor (ISA) in the railway sector focusing on software elements. He is a specialist in the field of software engineering (requirement engineering, semi-formal and formal method, proof and model-checking). He also works as an expert for the French notified body CERTIFER in the field of certification of safety critical railway applications based on software (ERTMS, SCADA, automatic subway etc.). His research interests include requirements, software verification and validation, traceability and RAMS with a special focus on SAFETY.

• INTRODUCTION ixCHAPTER 1. SAFETY MANAGEMENT 11.1. Introduction 11.2. Dependability 11.3. Conclusion 81.4. Bibliography 8CHAPTER 2. FROM SYSTEM TO SOFTWARE 92.1. Introduction 92.2. Systems of command and control 102.3 System 132.4 Software implementation 142.5. Conclusion 162.6. Bibliography 172.7. Glossary 17CHAPTER 3. CERTIFIABLE SYSTEMS 193.1. Introduction 193.2. Normative context 203.3. Conclusion 373.4. Bibliography 383.5. Glossary 41CHAPTER 4. RISK AND SAFETY LEVELS 434.1. Introduction 434.2. Basic definitions 434.3. Safety implementation 484.4. In standards IEC 61508 and IEC 61511 704.5. Conclusions 744.6. Bibliography 744.7. Acronyms 77CHAPTER 5. PRINCIPLES OF HARDWARE SAFETY 795.1. Introduction 795.2. Safe and/or available hardware 795.3. Reset of a processing unit 805.4. Presentation of safety control techniques 815.5. Conclusion 1175.6. Bibliography 1185.7. Glossary 119CHAPTER 6. PRINCIPLES OF SOFTWARE SAFETY 1216.1. Introduction 1216.2. Techniques to make software application safe 1216.3. Other forms of diversification 1496.4. Overall summary 1506.5. Quality management 1506.6. Conclusion 1556.7. Bibliography 1566.8. Glossary 157CHAPTER 7. CERTIFICATION 1597.1. Introduction 1597.2. Independent assessment 1597.3. Certification 1607.4. Certification in the rail sector 1617.5. Automatic systems 1717.6. Aircraft 1717.7. Nuclear 1717.8. Automotive 1727.9. Spacecraft 1727.10 Safety case 1727.11 Conclusion 1737.12 Bibliography 1747.13 Glossary 176CONCLUSION 177INDEX  179