Issues in the Runtime Modification of Software Architectures

Existing software architecture research has focused on static architectures, where the system architecture is not expected to change during system execution. We argue that the architectures of many systems, especially long running or mission critical systems, evolve during execution, and thus cannot be accurately modeled and analyzed using static architectures. To overcome these problems, we propose the use of dynamic architectures, where the system architecture may change during execution. In this paper, we identify the issues involved in supporting dynamic architectures. Although some of these issues may be addressed by augmenting current models (i.e., adding constructs that support dynamism to existing architectural description languages), many are new to dynamic architectures (i.e., runtime support for modifying architectures). We describe an initial implementation of our tool, ArchShell, that supports the runtime modification of C2-style software architectures.