In this paper we approach SW architecture through the needs and problems of object-oriented SW development. It is widely perceived that the OO approach - despite its generally acknowledged strengths - has so far failed to fully deliver its promises. Based on experiences from the development of several large embedded SW systems an analysis of common practical and conceptual problems in OO SW development is performed and a solution is suggested. The analysis indicates a need for SW architecture as a separate concept. The discussion of the solution concentrates on the nature of SW architecture in this context, on the methodological implications of combining SW architecture work with OO approach and on the role of the architecture task in the entirety of SW construction.