The Design And Implementation Of MDSL Based On The QNX Operating System

In recent years, real-time operating system is widely used in multimedia communication, online transaction processing, production process and traffic control, it play more important role in Research and Application. In numerous real-time operating systems, the micro kernel real-time operating system, owing to its characteristic of micro kernel structure, easily imbedded, real-time, it became a new trendence of the real-time technology. In addition,the micro kernel operating system offers the basic service function, other functions can be realized by dynamically loading related modules, the users can customize the operation system according to their demands, so it has higher flexibility. Multi-channel digital synchronous logger (MDSL) is designed by institute of image and graphics of Sichuan University. It is a necessary aerial apparatus for recording voice and radar datum between airplane and ground station of aerodrome. the previous versions MDSL are based on Windows or DOS operating system, because of structure and schedule algorithms of operation system, the MDSL can support limited number of channel; on the other hand, these versions MDSL need setup entire operating system environment, most functions of operating system never be used by MDSL, but any mistakes of operating system may affect MDSL stability,moreover, it need periodical human maintenance. For the above reasons, the author adopts QNX mirco kernel operating system as system platform, redesigning and coding MDSL based on QNX. QNX can be customized by demands of author, besides its kernel is small and easily imbeded, we can customize the QNX by the MDSL demands,and we can solidify the MDSL software. During the implementation of the system, Author solved two key problems, how to record the synchronous voice and radar data; how transfter the data stored in the local media to external storage. The full text has following three parts First part, Introduce background of the project, the overallly structure, system designing and author's work. The second part, according to demands of real-time processing of the voice and radar datum, bring forward receiving and writing methods and data stored structure, algorithms of search and replay data. The new designing MDSL can realize the real-time recording and replaying on condition that more channel number. Third part, according to demand of transfer local data, Author designed corresponding data transfer mechanism, adopted the USB flexible hard disk to be external storage. For this purpose, the author solved problems of end port communication and the management of the equipment under QNX with USB; instruction and data transmission according to specific protocols; mechanism for visiting file system. it make QNX operating system can use flexible hard disk in convenient measures, solved the problem of MDSL data transfered .