Arif Mehmood (FA12-RCS-045)
Research Article as Case Study-Advance Computer Architecture Course –MS (Computer Science) Comsats Institute of Information Technology/Department of Computer Science, Islamabad, Pakistan email@example.com
Abstract— Many applications like Military appliances for surveillance and monitoring, environmental sensing devices, traffic monitoring and many other applications use sensor networks to detect the environment. These sensor networks need specific software in the form of operating system to full fill the requirements. To achieve the goal, a very specific real time operating system Nano-RK has been designed and implemented very successfully. Nano R-K is reservation-based real time operating system. It is fixed-priority pre-emptive scheduling system to achieve the hard time deadlines. It supports the multi-hop networks and is used in wireless sensor networks. It is also characterised with managing the energy consumption in sensor nodes. It has been implemented on Atml ATMEGA128 processor with the chipcon CC2420 802.150.4 transceiver chip.
Key words: This paper describes different features of Nano-RK, a Real Time Operating System, characterized with multi-hop networking support and fixed priority pre-emptive multitasking.
The Nano-RK refers to its small size, Nano means it uses very small 2k RAM and 18k of flash . And RK is short for Resource Kernel. This kernel provides reservation for allocating different resources in different aspects like CPU reservation and network reservation. With the emerging technology of the sensor networks and its utilization in different applications brought challenges of designing software to operate the microcontroller found in sensor nodes. First work of providing the software support in the sensor networks was introduced by Hill, a computer scientist in his paper . He developed TinyOS to cope with the situation. After that, the very close work with respect to Nano- RK was done as Mantis OS. Due to several issues and shortcoming related with these attempts, an optimized and well suited real time OS was needed. Finally, the Nano-RK was developed to meet the sensor networks requirements, equipped with energy constrained environment and reservation based resource kernel
II. NANO-RK ARCHITECTURE
A. Static Strategy
Nano-RK utilizes static design-time strategy for controlling the energy usage. As compared to the general operating system, where the dynamic approach is used, the operating system and applications are found at the same address space. This strategy permits the programmers to manage the requirements of energy for applications and plan for provision of efficient energy throughout the life time of the system. Using this approach, the run time configurations are predefined by the developers and also power calculations are determined before the actual deployment of the system. Nano-RK architecture is shown in Figure 1.
B. Reserves (energy-aware resource-centric)
Nano-RK is characterized as reservation based system with respect to its components. The nodes, sensors, actuators, buffers of network, cycles of CPU are utilized according to the extent of requirement of application. Nano-RK ensures the timely meeting of deadline of tasks and well and balanced distribution of system slack cycles. There is also surety of guaranteed and timely access to the resources with limitation. The CPU time is reserved for the tasks, each task is provided with the CPU time as per reservation allocated to that task. As Nano-RK enforces the tasks to utilize the fixed period of time for sensor applications as determined by their requirement. The energy consumed by different nodes is counted by adding the energies utilized by the sensor, actuators, network and CPU. There may be a...