IC*: an environment for designing communications software

The modern phone network offers increasingly sophisticated services provided by increasingly complex software. This software controls and is responsible for maintaining the integrity of many semi-autonomous interacting systems, both hardware and software. Designing, specifying, and implementing such software requires an environment capable of expressing and managing its intrinsic parallelism. The IC* environment is being developed at Bellcore to meet this need. The current environment consists of the L.0 language and supporting tools. L.0 is an inherently parallel, object-oriented language based on the IC* model of synchronous, parallel computation. The current release of L.0 has not been optimized and is being used for simulation and prototyping rather than field release. This release runs on UNIX, IBM MVS, and Unisys 1100 systems and code developed for one is easily ported to the others. Parallel systems are very hard to understand statically, so the heart of the current environment is a set of tools for the audio-visual animation of executing specifications and for the production of prototypes. The designers and implementors of a new software system can observe it in action and play with it. The execution trace of a system's description can also be stored and browsed.<>