Mario Tokoro, Sony Computer Science Laboratories Inc.
Abstract
Today, most of the social infrastructure systems are supported by huge and complex software that must be dependable to provide sustainable services. However, such software systems inevitably involve incompleteness and uncertainty: incompleteness due to incomplete specifications and implementation which can be amplified by systems revision; and unpredictability due to requirements evolution, environmental changes, unexpected usage and attacks across networks. Therefore, it is almost impossible to treat such a system as a closed system whose functions and boundaries are fixed. Rather it must be approached as an open system whose dependability on huge and complex software systems is discussed and the notion of Open Systems Dependability is proposed. Then, the DEOS approach that integrates processes for development, operation and continuous revisions is described with the architecture which realizes the system.