Model of GERT-networks for different ways of usage of multi-version methodology

This article describes different ways of application of multi-version methodology in the development of multi-version fail-safe software, and presents models of multi-version software architectures in the form of basic GERT-networks. With respect to the necessary and sufficient condition for the operation of multi-version module, the node with IOR input and output is selected to provide deterministic network section that describes the module. Formulas for calculation of probabilistic-time characteristics of multi-version modules, that provide fitness of GERT-network models to describe multi-version software, are presented. This allows to use the equivalent conversion and existing methods of calculation of GERT-networks.