InterBase: An Execution Environment for Global Applications over Distributed, Autonomous and, Heterogeneous Software Systems

Existing and well entrenched hardware and software systems are the product of lengthy and individual developmental histories. The introduction of harmonious cooperation among such systems carries the potential for great increases in productivity and improvement in applications processing. However, the utilization of these heterogeneous components is hampered by the absence of an integrated system that would allow the development of global applications requiring communication and cooperation among existing systems. Designed to integrate pre-existing systems over a distributed, autonomous, and heterogeneous environment, and to support global applications while retaining local autonomy, the InterBase System overcomes this heterogeneity barrier. The fundamental underpinning of this system is the InterBase Parallel Language
(IPL), which provides an interface allowing users to write global applications over such an environment. IPL supports flex transactions [ELLR90] and provides commitment constructs that allow users to define their own commitment protocols; both features are superimposed upon the component pre-existing systems. Remote System Interfaces are provided as a mediator to
deal with the heterogeneity of these pre-existing systems and to present a uniform system-level interface to IPL programs and their interpreter. A Distributed Flexible Transaction Manager serves to interpret IPL Programs and to coordinate their executions. Based on the concept of Quasi Serializability [DE89, ED91], a Distributed Concurrency Controller has been developed to manage the parallel read/write accesses to the pre-existing systems. The system presented here is modular and is ideally suited to heterogeneous hardware, software, and network environments, particularly multidatabases. This paper explores the issues of system architecture, language design, concurrency control, and system interfaces in such a project. As a case study, we also discuss such a system which is currently in use at BNR Inc.