The domain of operating systems has often been mentioned as an “ideal candidate” for the application of AOP; fundamental policies we find in these systems, such as synchronization or preemption, seem to be inherently cross-cutting in their implementation. Their clear separation into dedicated aspect modules should facilitate better evolvability and – the focus of this paper – configurability. Our experience with applying AOP to the domain of highly configurable embedded operating systems has shown, however, that these advantages can by no means be taken for granted. To reveal maximum configurability of central system policies, aspects and their potential interactions with the system have to be taken into account much earlier, that is, “from the very beginning”. We propose the analysis and design process of aspect-aware development, which leads to such an “aspect-friendly” system structure and demonstrate its feasibility on the example of CiAO, an AUTOSAR-OS-complia...