Automated aircraft control has been divided into independent functions such as Auto-Pilot, Flight management etc.. that are  Each of these functions is implemented separately and has its own fault-tolerant system.  So dependencies among different functions are limited only to sensor and control data exchange. In Federated systems / architecture, faults are strictly recommended to be restricted within the system’s function, and faults propagation is not possible, so the operation of  one function will not be affected due to a fault in other function. Modern avionics architectures are degined to support multiple functions on a single fault-tolerant system with shared architecture where fault containment boundaries are not well defined.   

While building large complex real-time systems, separated application modules are integrated to achieve reliability, reusability, and cost reduction. An essential requirements of integrated real-time systems is to guarantee strong partitioning among applications. Partitioning needs correct hardware and software architecture to keep strict fault containment in  integrated architectures. In a Partition Operating System, memory is divided among statically allocated partitions in a fixed manner. By completely isolating the subsystems, it gives the illusion of working with multiple processors instead of just one processor.