Analysing dynamic change in distributed software architectures

The software architecture of a system is the overall structure of the system in terms of its constituent components and their interconnections. Dynamic changes to the instantiated system architecture (to the components and/or interconnections) may take place while it is running. In order that these changes do not violate the integrity of the system, we adopt a general model of dynamic configuration which only permits change to occur when the affected portions of the system are quiescent. This paper investigates the feasibility of performing behaviour analysis on systems which conform to the change model. The analysis approach associates behavioural specifications with the components of a software architecture and analyses the behaviour of systems composed from these components. The changes that can occur are modelled as constraints on the architecture, thereby permitting incremental and even concurrent changes. Analysis is used to check that the architecture satisfies the properties required of it: before, during and after the changes. The paper uses an example to illustrate the approach