Odaruschenko E. The fault-tolerant computer systems modeling with changes flow parameters of software failure and renewals accounting

Object – processes of the modeling and dependability estimation of the fault-tolerant computer systems. Target of research - to increase the accuracy of modeling and the estimation of the dependability (availability) of the fault-tolerant computer systems based on detailing plurality of the system states account the change of software failure and renewals flow rate. Basic methods of research are the methods of the theory of chances, system and Markov analysis, mathematical modeling, theory of graphs, mathematical statistics, imitation modeling. Scientific results are: method of mathematical description of the fault-tolerant computer systems states, which is based on presentation of their models as repetitive fragments, unlike existing takes into account the discrete change of one or a few parameters, that allows to reduce charges for development of base models due to their normalization and directed choice depending on the variants of change of failure and renewals flow parameters; Markov models of thefault-tolerant computer systems dependability which are based on their multi-fragment presentation and take into account the change of software failure and renewals flow rate, that allows to promote exactness of design and estimation of dependability indexes; the exponential method of numeral decision of the hard systems of differential equalizations of Kolmogorov is modified, which is based on application of procedure of calculation of step of integration depending on the maximal value of element of matrix of coefficients and chosen constant, that allows to decrease expenses of machine time at the calculation of the fault-tolerant computer systems dependability indexes. Introduction is branch-based. Fields of use – development of the technical and organization-technical computer complexes of the critical usage.