In this paper, we have presented the scheduling architecture proposed in the FIRST (Flexible Integrated Real-Time Scheduling Technologies) project. It provides for the coexistence and cooperation of diverse real-time scheduling schemes, in particular table driven, fixed priority, and earliest deadline, and integrating of different task types such as hard and soft, or more flexible notions. The FIRST scheduling framework, FSF, proposes a hierarchical scheduling structure based on servers. Application requirements are defined as service contracts which provide an interface layer to the underlying servers provided by the operating system. Contracts can be verified at design time by providing off-line guarantees, or can be negotiated at runtime, when they may or may not be admitted.