The design of I/O subsystem in satellite real-time microkernel operating system

One of the most important features of modern minor satellites is to realize autonomous moving. The performance of the satellite autonomous computer operating system acting as the control center is utmost important. The recent trend in operating system development is adopting rnicrokernel architecture which holds such advantages as microminiaturization. modularity, portability and extendibility. The performance of I/O subsystem is currently receiving considerable research attention. Object-orientation offers an approach to application development in which software system can be constructed by composing and refining the pre-designed plug-compatible software components. It also starts with some basic notions fairly well accepted in computer science, namely encapsulation and reuse. In this paper, a new object-oriented real-time I/O subsystem model has been designed. In this model, the traditional I/O subsystem framework is discarded and a stream mechanism based on the object-oriented concept is introduced. In addition. the I/O requests are classified according to their time emergency to obtain real-time performance. So. this model meets such satellite performance requirements as reliability, flexibility. portability and real-time performance.