Quality of service facilities for firm real-time energy harvesting systems

Embedded systems become part of our modern life. Most of them have real-time performance requirements that must be met for reasons of security, safety and usability. Nevertheless, someones have low performance requirements and allow simplifying the system hardware to reduce costs. In this paper, we deal with a real-time embedded system composed of one processor that executes a set of firm periodic tasks i.e. cyclic tasks that may occasionally skip instances. The computing system is connected to a rechargeable battery that is powered by a renewable energy such as solar energy. The goal is to enhance Quality of Service (QoS) of this system measured by the ratio of deadlines actually met, considering both energy and time constraints. In this objective, we propose a new scheduling mechanism called Green-RTO to be integrated in the operating system for any firm real-time energy harvesting application.