Much work has been done in the last decade in the related areas of object-oriented programming languages and object-oriented databases. Researchers from both areas now seem to be working toward a common end, that of an object management system, or OMS. An OMS is constructed similarly to an OODB but provides a general purpose concurrent object-oriented programming language as well, complementing the OODB query facilities. In this paper, we will define several different types of object systems (object servers, persistent OOPL’s, OODB’s and OMS’s) in terms of their interfaces and capabilities from the viewpoint of how these support the requirements of cooperative information systems. We will examine the distinguishing features and general architecture of systems of each type in the light of a general model of OMS architecture.

Distributed concurrency control has been implemented by representing in-progress transactions as simulated objects, called transaction objects, that use normal message passing facilities. The implementation of an optimistic mechanism has been completed using transaction objects and a two-phase locking mechanism has been designed. The tradeoffs made and lessons learned, dealing with transactions both on objects and as objects, are discussed.>