(Re-) configurable real-time operating systems and their applications

There are trends in the area of real-time computing to shift from RTOS kernels (fixed or configurable ones) to more flexible approaches, where a RTOS (real-time operating system) is generated exactly in the way it is needed for a specific application context. One example for this approach is the component library Dreams, developed at HNI of Universitat Paderborn. This library offers a fine granular set of components that can be customized at source code level and configured in a very flexible way. The needed configurator, also developed at HNI, is called TEReCS. It allows mapping specific application needs exactly onto the needed and properly customized stet of Dreams component. The available hardware resources are taken into consideration as well. In this paper, we describe how this potential has been used or can be used for rather different classes of applications. The three application examples considered origin from the control of flexible manufacturing systems, synthesis of distributed embedded software, and the real-time image processing needed to offer virtual camera positions in broadcasting sports events. In the first application example, it is discussed how the control of flexible manufacturing systems (so-called holonic approach) can be interpreted as a special kind of a ROTS and which configuration needs have to be considered. In the second example, a model of distributed embedded systems by means of hierarchical predicate/transition nets (a special kind of higher order Petri nets) is directly transformed into a specially configured RTOS. Finally, in the third example, a very special application is considered. From a fixed camera position at known locations, the image that would be produced by a camera position at an arbitrary location (virtual camera) is calculated. This application is intended for sports events like soccer matches. As this, obviously, has to happen in real-time, sophisticated support by a properly tailored RTOS running on processor clusters has to be provided. For this application we decided to configure RTAI Linux in a proper way.