is a collection of UNIX* based software tools within an architecture that facilitates the development of new interactive, integrated software systems with significant productivity gain. The main characteristic of this environment is that it encourages a high degree of reusability, especially at the architecture and program level, and it provides facilities for the development of software through rapid prototyping.Further, it is an environment with an open architecture and as such it can easily be extended to meet the variety of needs of its diverse user community.