1.  CS 5380 Software Engineering Chapter 11 Dependability and Security

2. Section 2  Section2 Dependability and Security  Ch 10 SocioTechnical Systems  Ch 11 Dependability and Security Chapter 11 - Dependability and Security

3. Objectives – Chapter 11  First page of chapter Chapter 11 - Dependability and Security

4. Dependability  Several topics  Availability  Reliability  Safety  Security  Each has further subtopics Chapter 11 - Dependability and Security

5. Problem based learning  Student takes responsibility for learning  Solution of a problem is the foundation for learning the key principles  Different from  Lecture  Lecture/application of principles Chapter 11 - Dependability and Security

6. Availability  Probability that a system is up and working  Measurement  Max time down per instance  Max number of times down  Percentage of time down  May vary with time of day / day of week  Allow for nighttime maintenance  System may have multiple measurement points  Can involve many aspects  Hardware, network, power, OS, maintenance,  Affected by system load Chapter 11 - Dependability and Security

7. Availability  Real time systems (robotics, automotive)  Control systems (industrial)  Embedded (printers, medical equipment)  Communications (phone, network)  Financial Chapter 11 - Dependability and Security

8. Reliability  Probability of failure free operation  Measurement  Time between failures  Failure per transaction  Failures per time  Depends heavily upon the operation  Multiple values  Depends on data  Different types of data exercise different aspects of sotware Chapter 11 - Dependability and Security

9. Reliability  Real time systems (robotics, automotive)  Control systems (industrial)  Embedded (printers, medical equipment)  Communications (phone, network)  Financial Chapter 11 - Dependability and Security

10. Safety  Never harm people or property  Even if system fails to operate  Power, network, hardware, system load  Primary vs Secondary  Insulin Pump  CAD  Author: Malfunctions often related to requirements specification  Hardware failure consideration Chapter 11 - Dependability and Security

11. Safety  Hazard avoidance  Car navigation system – disabled when vehicle moving  Hazard detection  Pressure, temperature, speed sensors  Car – distance sensor  Damage limitation  Insulin pump – manage failure of sensor. Chapter 11 - Dependability and Security

12. Security  Protection from threats  Intentional  Unintentional  Tsunami/earthquake Chapter 11 - Dependability and Security

13. Security  Security from  Modification  Theft  Layers of Protection  Networking  Logon  Authentication  Limitation of data access Chapter 11 - Dependability and Security

14. Security Terminology  Assets  Exposure  Vulnerability  Attack  Threat  Control Chapter 11 - Dependability and Security

15. Dependability  Repairability  Trace of activities  Error logs / meaningful errors  Maintainability  Much software evolves  Survivability  Resistance to attack  Threat identification  Error Tolerance Chapter 11 - Dependability and Security