Publisher FrameWork (PFW)

One of the lasting challenges in building distributed fault tolerant systems is keeping application code size and complexity down. This can be done by capturing the nuances of distributed computing environment and redundant fault tolerant elements into a common infrastructure layer, thus factoring the code that would otherwise need to be written again and again by each distributed fault tolerant software component. When the application code has many complexities, and Air Traffic Control (ATC) is certainly one such example, achieving this goal becomes paramount.Under a project called En Route Automation Modernization (ERAM), the Federal Aviation Administration (FAA) is developing a replacement for its aging en route assets. At the same time, a foundation is being created for the anticipated future enhancements, driven by the projected increase in air traffic. At the core of the ERAM design is a distributed object oriented (OO) framework called Publisher FrameWork (PFW), which is ERAM's answer to the aforementioned OO challenge. This paper describes the PFW properties, the experiences with it accumulated through the first build of the ERAM program, and its applicability to fault tolerant computing.