1. Fault Tolerance Distributed
ITV Model-based Analysis and Design of Embedded Software
Techniques and methods for Critical Software
Anders P. Ravn
Aalborg University
August 2011

2. FT basis: Redundancy
Time
Space
Try
Retry
Retry
...
Try
...
BW p. 109

3. Fault Tolerance

4. Basic Strategies

5. Example

6. Fault Hypotheses

7. Fault-Tolerant System

8. Impulse Generator

9. CU

10. Voter and Arbiter

11. Parameters

12. Properties

13. Procedure
Model the correct component and check that it has the desired properties.
Model relevant faults and introduce them as internal transitions to error states. Check that this is fault-affected.
Introduce into the model the mechanisms for fault detection, error recovery and masking and check that the desired properties are valid for this design.