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

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

Fault Tolerance

Basic Strategies

Example

Fault Hypotheses

Fault-Tolerant System

Impulse Generator

CU

Voter and Arbiter

Parameters

Properties

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.