Event services have received increased attention as scalable tools for the composition of large-scale, distributed systems, as evidenced by their successful deployment in interactive multimedia applications and scientific collaborative tools. This paper introduces KECho, a kernelbased event service aimed at supporting the coordination among multiple kernel services in distributed systems, typically to provide applications using these services with certain levels of Quality of Service (QoS). The publish/subscribe communication supported by KECho permits components of remote kernels as well as applications to coordinate their operation. The target group of such a kernel-based event service is the rapidly increasing number of extensions that are being added to existing operating systems and are intended to support the Quality of Service and real-time requirements of distributed and embedded applications.
