SPECIFICATION OF CONCURRENCY: AN OBJECT-BASED APPROACH

The authors present an object-based model that stresses the property of parallelism: parallel objects (PO). The main goal of an environment based on PO is to allow the user a maximally parallel decomposition of its applications. Two types of parallelism, interobject and intraobject parallelism, are utilized. The former results from the intrinsic capacity of execution associated with any object. The latter is guaranteed by the concurrent presence of activities within the same object. Thus, the PO scenario is made up of active objects that may have several internal activities going on simultaneously. The authors focus on intraobject parallelism and its expression; it is obtained by high-level specifications. This features takes advantage of the uniformity and dynamicity of object systems. Intraobject behavior can be decided and updated on an object base. In PO, several different concurrency strategies can be investigated and rapidly prototyped. PO is particularly suited to applications whose specifications have a high rate of updating