However for dynamic change to yield valid systems, change actions must be carried out such that the consistency of the software modules making up the system is not breached. This can be ensured if the subset of the system which is to undergo change is in a state amenable to reconfiguration. This paper presents an algorithm which imposes a safe state over the part of the system undergoing change. The algorithm suits a particular class of transactional systems and places special emphasis on minimising the interference to the rest of the system and reducing the programmer contribution necessary for achieving this safe state. This paper describes an environment for interactive configuration management of software for distributed applications and services.
Components register both required and provided interfaces in a domain service.
We describe a graphical configuration environment, based on the Darwin Configuration language, which can be used to create the required configurations, and maintain the configuration structure as part of the overall systems management infrastructure. The paper describes a simple example to show how an initial system can be initially constructed and subsequently reconfigured at run-time without shutting down the system. The technique is applied by a repetition of local analyses, the basic steps to construct and examine the behaviour of subsystems. These behaviour constraints are normally not considered when using local analysis in conventional techniques of compositional reachability analysis. As a result, many execution paths derived in the local analysis may not be actually traversed by the subsystem.