An efficient data scheduling policy in operating system for wireless sensor platforms to build fast query

It is going to be prescribed a dynamic multithreaded Operating System for wireless sensor network platforms. This operating system provides a cooperative threading model, for Underwater Sensor Network applications. Virtual memory is supported with the cooperation of the compiler, so that the sensor network platforms can execute code larger than the physical code memory they have. To enable firmware update for deployed sensor nodes, presented operating system supports remote reprogramming. The proposed techniques do not increase hardware cost, and are designed to require few changes to existing applications. It has been developed a compression algorithm well suited to this application. The commonly used library and the main logical structure are separated; each sensor device has a copy of the dynamic loading library in the MMC card, and therefore only the main function and user-defined subroutines can be updated through RF. A dynamic, efficient file system named Flash File System is also included in OS. The code size and data size of OS including Flash File system are 8kB and 646 bytes, respectively.