The Research And Implementation Of Some Key Software Technologies For γOS Operating System Which Supports Wireless Networked Sensors

With the development of pervasive computing technologies, the wireless networked sensor, which integrates the ability of sensing, actuating, computing and communicating, will be widely used in various regions. Compared with traditional computation device, wireless networked sensors have the following characteristics: small physical size and low power consumption, diversity in design and usage, limited physical parallelism and controller hierarchy, robust operation, concurrency-intensive operation, and so on. The design of system software in sensors constitutes a challenging research field. The traditional operating systems and programming technologies are not suitable for wireless networked sensors directly. Therefore, it is required that we should research and develop a new super-micro embedded operating system and programming model to manage and operate these kinds of devices.Aiming at the applications of wireless networked sensors in smart-homesystem, in this thesis, we focus on some key software technologies, including thesuper-micro embedded operating system kernel, wireless network protocol andsystem programming language. And we design and implement the super-microembedded operating system γOS, which supports the wireless networked sensors.The main contents and contributions of the work are as follows:1. Design and implement the γOS operating system framework that supportswireless networked sensors. Based on the research and analysis of variousoperating systems for sensors, to meet the requirement of the design inwireless networked sensors, we present a new framework for sensoroperating system γOS. With the supporting of AntC compiler, γOSimplements configurable modularized system function design, and achievesmicromation and integration. By dividing system functions into components,γOS can make use of different components to assemble correspondingapplication program. According to the user-defined component model and thethinking of object oriented programming, γOS provides a universal interfaceof component, and achieves high re-utility of code. Based on the event-drivenmicro-thread frame, γOS achieves simple but efficient running mode,including the interacting between sensor and environment, and the supporting of concurrency.2. Analyze and design the kernel of yOS operating system which supports reliable task scheduling mechanism. We analyze the task model of wireless networked sensors, including hardware model, process model and task set. We present the yOS grouping task scheduling mechanism that supports priority division to schedule time-critical taks and non-time-critical tasks separately. Based on this scheduling mechanism, we present a schedulability analysis algorithm, which is implemented by making use of the schedulability analysis technique based on CPU utilization and the Rate-Monotonic scheduling algorithm. Aiming at the robustness requirement in sensor operating system, we present a fault tolerance scheduling mechanism for yOS, including the fault detect, fault recovery and schedulability analysis. The fault detection and fault recovery are implemented based on primary/alternative task fault-tolerance mechanism, and the schedulability analysis is based on Rate-Monotonic scheduling algorithm.3. Design and implement the wireless networked protocol in yOS MAC layer for wireless networks sensors. Based on the application analysis of wireless networked sensors in smart home system, we present a reliable wireless network protocol in MAC layer named ST-MAC. It includes the definition of data packet format based on active message, the media access control strategy, the network adaptive strategy and the time synchronization strategy that make use of master/slave mode and TDMA scheme, and the power saving listening mechanism. The experiments shows that ST-MAC achieves adaptive power control in communications to save power, efficient transmission control for high packet delivery success rate, fair bandwidth allocation for all nodes in the network and acceptable adaptive ability when the sensor network changes.4. Design and implement the system programming language for yOS operating system. To implement the concept in yOS design, we present the system programming language AntC. AntC supports the yOS component model, micro-thread system frame, task scheduling scheme and wireless networkprocotol directly. The contribution of AntC is as follows: implement an event driven model, a flexibility concurrency model and a component oriented programming model to meet the special requirement in this region. The AntC compiler can provide static data race detecting, static component instantiating, the whole program inline, the dead code cleanup, and other mechanisms about global analysis and optimization. By making use of global analysis and optimization, it is beneficial for AntC compiler to generate nicer executive code and reduce the factor of inducing bug. AntC compiler provides a good balance among enhancing the reliability of program, controlling the code size of program and improving the behavior of program.