The distributed data protocol within OOPAR

Abstract. This contribution describes a distributed data protocol as implemented in the object oriented programming environment OOPAR. OOPAR develops a paradigm for the development of parallel algorithms based on the concepts of tasks which act on distributed data. The task objects which implement a part of the parallel program depends on data objects with specific version to operate. The dependency of the tasks with respect to the data are registered by a data manager which takes actions to satisfy the tasks request. The procedure implemented by the data manager resembles a distributed data access protocol and is docu-mented in the paper. Its main features are:-the administration is per-formed in a distributed manner (there is no ”central processor ”-objects are transmitted between processors only if needed-several processors can access an object simultaneously if they requested read access-the administration guarantees the consistency of access states if the requests are consistent-tasks which request access to objects with version older than the actual version of the object are automatically canceled.