Dependable Reuse & Guarded Integration of Automotive Software Components Approaches to Conditional Specification & Assurance

The assembly of software components to a properly functioning system is a key problem in the development and maintenance of software for safetycritical, real-time systems. The integration of binary components may take place during integration testing or at run time (updates, patches, adaptation, ...). It would be even more advantageous to be able to integrate components “virtually” already during the design phase, to analyze their interaction early and possibly fix any specification errors before implementation. The concept of virtual integration requires modular and semantic component descriptions that go beyond the usual specification of syntactic interfaces. The core idea is to split descriptions into requirements of the component on environment inputs on one side, and assertions about the properties of the component’s output on the other, provided the requirements are fulfilled. There exist several approaches to the realisation of this concept, called assume-guarantee/rely-guarantee/assumption-commitment reasoning, Design by contract, Rich components etc (subsumed in the present report as “conditional specification” or “conditional assurance”, respectively). Mostly they are basic research and have not been consistently applied so far in the context of automotive software or embedded systems development. The objectives of this project are  a survey of previous work in the area of conditional assurance,  the classification of identified approaches in a practical schema,  the exemplary application of a selected approach to a concrete system model and scenario.