As IoT (Internet of Things) is prevailing, the number of devices which have strict resource constraints is increasing. In developing such a system, RTOS (Real Time Operating System) helps to increase productivity. However, in the view of cost reduction, it is desirable that resources for RTOS be small and the execution time be short. In this paper, we propose a method to develop an application-specific system with RTOS. Methods of removing unnecessary code for the application from RTOS kernel are explained. In addition, we implemented a reconfigurable hardware RTOS on an FPGA and applied the method for removing unnecessary code from the hardware implementation. The evaluation results show that the proposed methods reduce hardware resources, RTOS kernel execution time, and the size of the software parts in each application.------------------------------This is a preprint of an article intended for publication Journal ofInformation Processing(JIP). This preprint should not be cited. Thisarticle should be cited as: Journal of Information Processing Vol.28(2020) (online)DOI　http://dx.doi.org/10.2197/ipsjjip.28.395------------------------------

As IoT (Internet of Things) is prevailing, the number of devices which have strict resource constraints is increasing. In developing such a system, RTOS (Real Time Operating System) helps to increase productivity. However, in the view of cost reduction, it is desirable that resources for RTOS be small and the execution time be short. In this paper, we propose a method to develop an application-specific system with RTOS. Methods of removing unnecessary code for the application from RTOS kernel are explained. In addition, we implemented a reconfigurable hardware RTOS on an FPGA and applied the method for removing unnecessary code from the hardware implementation. The evaluation results show that the proposed methods reduce hardware resources, RTOS kernel execution time, and the size of the software parts in each application.------------------------------This is a preprint of an article intended for publication Journal ofInformation Processing(JIP). This preprint should not be cited. Thisarticle should be cited as: Journal of Information Processing Vol.28(2020) (online)DOI　http://dx.doi.org/10.2197/ipsjjip.28.395------------------------------