Using iDAVE to determine availability requirements

Different systems have different success-critical stakeholders. Even for the same system, these stakeholders may depend on it in different ways for different scenarios. Therefore a one-size-fits-all dependability metric is unachievable in practice. In order to cost-effectively achieve the stakeholders' desired dependability attribute requirements for a given project, we have to solve such problems as how to define an appropriate level for a particular dependability attribute and how much dependability investment is enough for a particular software/scenario class. However, the answers to those questions are traditionally difficult to obtain. This paper uses a hypothetical Lunar Biological Laboratory (LBL) as an example to illustrate how to use the iDAVE model to determine the appropriate levels of availability requirements for different software/scenario classes based on their different ROI profiles.