The software stochastic model of operating behavior of failure-resistant systems with majority type of voting {3 of 5} is intended for information technology design of communication or technological systems of critical infrastructure facilities.
The development of states-transitions model is an important stage in the technology of
the development of the discrete-continuous stochastic models of fault-tolerant systems. There
is a known method of developing the states-transitions model, which is based on an algorithm
of constructing the state-transitions models out of so-called “structural-automaton model”.
This method is implemented in a software tool prototype called “ASNA”. If structuralautomaton
model is errorless, resulting states-transitions model will be errorless as well.
Designing of radio-electronic systems of responsible purpose with hardware-software implementation involves the mandatory provision of their property of fault-tolerance. The property of fault-tolerance are provided by the use of fault-tolerant systems. For these fault- tolerant systems at the stage of system engineering design it is necessary to solve the problem of reliability structural-parametric synthesis. A designer must have a high degree of adequacy of reliability models of fault-tolerant systems with different configurations to solve such a task.
The problem of the conditions definition of the transition from the corrective recovery to the planned recovery strategy of an uninterruptible power supply, while a reliability is kept on the same level, is considered in this paper.
We consider the uninterruptible power supplies (UPS), which have a modular structure of the power supply unit (PSU). They are designed as a fault-tolerant systems (FTS) with N+M and 2×(N+M) redundant configurations, where N - is number of the PSU modules required to power the workload, and M - the number of the redundant modules.