This paper presents a two-level model of distributed computation designed to provide a formal basis for specifying and reasoning about dynamic system modification and resource management activities in a distributed system. We take actors as our underlying computation model. An important role of such a model is to represent interactions among resource management activities and between system level activities and application level activities. This allows us to express and reason about properties such as non-interference and composability. We illustrate the use of our model to specify resource management activities such as garbage collection, global distributed snapshots, dynamic insertion of dependability protocols and authentication mechanisms.
Keywords: distributed objects, actors, garbage collection, replication, security, distributed snapshots, acquaintances.