Ponochovniy Y. Models and methods of information systems dependability providing taking into account of software update processes

Dissertation is devoted to development and perfection of estimation and providing models, methods, tools of information systems dependability taking into account of hardware and software failures and software update processes. Scientific results are: 1) Model of failure rate of software information systems, with are caused by malicious faults is obtained for the first time. This model is based on a statistical data handling about attacks and takes into account, as against known, parameters of software faults and actions to the system, which allows providing required dependability level of information systems with updated software in these conditions. 2) The method of information systems dependability estimation is developed. It is based on double-lever representation of systems states, takes into account the failures, caused by hardware-software faults and exterior actions. The method allows rising exactitude of an estimation of an index of information systems availability measure. 3) The method of information systems dependability rising has received the further development. It is based on choice of types and parameters of software update procedures and allows increasing systems availability at the expense of defect elimination an operation phase. The offered methods are realized as estimation models, engineering methods and algorithms of dependability estimation and increase. They are the tools of information technology of the information system dependability providing.