Chapter 5
GAFT Generalization: A Principle
and Model of Active System Safety
Abstract Fault tolerance so far was considered as a property of a system. In fact
and instead, we introduce a Generalized Algorithm of Fault Tolerance (GAFT) that
considers fault tolerance as a system process. There is no doubt we have to analyze
GAFT implementation using redundancy types of computer systems. Properties of
GAFT implementation impact on overall performance of the system, coverage of
faults, and ability of reconfiguration.
It is clear that separation of malfunctions from permanent fault simply must be
implemented and reliability gain is analyzed. A ratio of malfunctions to permanent
faults is achieving 10
5−7 and simple exclusion from working configuration a malfunctioned element is no longer feasible.
In this chapter, we consider GAFT extension in terms of generalization and
application for support of system safety of complex systems. Our algorithms of
searching correct state, “guilty” element, and analysis of potential damages become
powerful extension of GAFT for challenging applications like avionic systems,
aircraft as a whole.
Until now, we were introducing the GAFT as the algorithm of achieving
property of fault tolerance in a system as a process. What we did not yet cover is
how to figure out a system approach or method of finding which hardware or
software components are affected by a fault. We want to tackle this problem in this
chapter.
The Method of Active System Safety (MASS) [1] provides a mathematical
approach for the diagnosis and prognosis of faults in real time during system
execution. It is based on the description of a system (of objects) and the dependencies between components and elements of the system represented as a matrix.
Every entry in the dependency matrix represents a dependency of one element to
another. Represented as a graph, dependencies are just directed edges between
elements. Two elements a and b can also be mutual dependent on each other which
is represented by two edges with opposite direction between these elements.
© Springer Nature Switzerland AG 2020
I. Schagaev et al., Software Design for Resilient Computer Systems,
https://doi.org/10.1007/978-3-030-21244-5_5
47
GAFT Generalization: A Principle
and Model of Active System Safety
Abstract Fault tolerance so far was considered as a property of a system. In fact
and instead, we introduce a Generalized Algorithm of Fault Tolerance (GAFT) that
considers fault tolerance as a system process. There is no doubt we have to analyze
GAFT implementation using redundancy types of computer systems. Properties of
GAFT implementation impact on overall performance of the system, coverage of
faults, and ability of reconfiguration.
It is clear that separation of malfunctions from permanent fault simply must be
implemented and reliability gain is analyzed. A ratio of malfunctions to permanent
faults is achieving 10
5−7 and simple exclusion from working configuration a malfunctioned element is no longer feasible.
In this chapter, we consider GAFT extension in terms of generalization and
application for support of system safety of complex systems. Our algorithms of
searching correct state, “guilty” element, and analysis of potential damages become
powerful extension of GAFT for challenging applications like avionic systems,
aircraft as a whole.
Until now, we were introducing the GAFT as the algorithm of achieving
property of fault tolerance in a system as a process. What we did not yet cover is
how to figure out a system approach or method of finding which hardware or
software components are affected by a fault. We want to tackle this problem in this
chapter.
The Method of Active System Safety (MASS) [1] provides a mathematical
approach for the diagnosis and prognosis of faults in real time during system
execution. It is based on the description of a system (of objects) and the dependencies between components and elements of the system represented as a matrix.
Every entry in the dependency matrix represents a dependency of one element to
another. Represented as a graph, dependencies are just directed edges between
elements. Two elements a and b can also be mutual dependent on each other which
is represented by two edges with opposite direction between these elements.
© Springer Nature Switzerland AG 2020
I. Schagaev et al., Software Design for Resilient Computer Systems,
https://doi.org/10.1007/978-3-030-21244-5_5
47