Data Diverse Software Fault Tolerance Techniques for C3I Technologies

The objectives of this effort were to:- Invent new data diverse software fault tolerance techniques with a focus on those techniques most appropriate for use with Command, Control, Communications, and Intelligence (C3I) technologies.- Develop an intelligent design aid to help users select candidate software fault tolerance (SWFT) techniques for their application, evaluate those techniques using a SWFT modeling and analysis tool, select the best technique based on candidate selection criteria and simulation results, and implement the technique(s) using reusable code.The SWFTDA (Software Fault Tolerance Design Assistant) tool acts as an intelligent design assistant to guide the software developer in implementing software fault tolerance where most appropriate and effective. To do this, SWFTDA uses the software developer¿s expertise about the application system, combined with SWFTDA¿s built-in expertise about software fault tolerance. SWFTDA also provides the building blocks for modeling and implementing software fault tolerance. The purpose of the SWFTDA is to help users - determine whether to apply SWFT techniques in a particular application, - select candidate data diverse SWFT techniques for their applications,- evaluate those techniques using a modeling tool,- choose the recommended technique based on candidate selection criteria and simulation results, and - implement the recommended technique using reusable code.SWFTDA was qualification tested by examining a database controller for a commercial order processing and workflow system. The most appropriate software fault tolerance techniques for the application were determined by SWFTDA. The system was modeled using modeling templates of the candidate techniques. Based on the simulation results and trade-off analysis, a final technique was selected for implementation. The technique was implemented using the reusable code library developed for use with SWFTDA.