text: Multi-mode real-time systems are those which support applications with different modes of operation, where each mode is characterized by a specific set of tasks. At run-time, such systems can, at any time, be requested to switch from its current operating mode to another mode (called "new mode") by replacing the current set of tasks with that of the new-mode. Thereby, ensuring that all the timing requirements are met not only requires that a schedulability test is performed on the tasks of each mode but also that (i) a protocol for transitioning from one mode to another is specified and (ii) a schedulability test for each transition is performed. We propose two distinct protocols that manage the mode transitions upon uniform and identical multiprocessor platforms at run-time, each specific to distinct task requirements. For each protocol, we formally establish schedulability analyses that indicate beforehand whether all the timing requirements will be met during any mode transition of the system. This is performed assuming both Fixed-Task-Priority and Fixed-Job-Priority schedulers.
  @cite_16: It is noted that in many hard real-time systems, the set of functions that a system is required to provide may change over time. One way of providing this change is to allow currently running hard real-time tasks to be deleted or changed, or new tasks to be added. The authors define this change as a mode change, and seek to guarantee a priori the timing constraints of all tasks across the change from one mode to another. The authors derive a scheduling theory for static priority preemptive scheduling that can be used to make such guarantees. The schedulability test discussed could easily be incorporated into engineering support tools. The authors also discuss some of the approaches that could be taken to extend the analysis to cope with more complex and interesting scheduling problems, and to handle distributed hard real-time systems. >
  @cite_22: One important requirement of many real-time systems is the ability to undergo several mutually exclusive modes of operation. By means of a mode change the system changes its functionality over time, thus being able to adapt to changing environmental situations. In order to successfully include mode changes in real-time systems, a mode change protocol with well known real-time behaviour is necessary. The authors provide a new model and related schedulability analysis for mode changes in flexible real-time systems.
summary: The authors of @cite_16 introduced a particular protocol which allows tasks to modify their parameters (period, execution time, etc.) during the mode changes. As in @cite_22 , this study assumes that the tasks are scheduled according to the Deadline Monotonic scheduling algorithm.