Integrating QoS management in a micro-kernel based UNIX operating system

We present a prototype that supports distributed applications handling continuous media such as digital audio and video with Quality of Service requirements. It provides Quality of Service guarantees, rather than a best effort behaviour. Our prototype is based on a modular UNIX operating system in which system resources (such as CPU, network, and file system) are managed by individual components, that can be enhanced to supply the QoS. The global QoS is managed by a component that coordinates the behaviour of the managers and that interfaces the applications. We show how this model has been implemented in a distributed operating system, namely Chorus/MiX, for supporting both applications handling continuous media and standard applications.