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_9: The problem of multiprogram scheduling on a single processor is studied from the viewpoint of the characteristics peculiar to the program functions that need guaranteed service. It is shown that an optimum fixed priority scheduler possesses an upper bound to processor utilization which may be as low as 70 percent for large task sets. It is also shown that full processor utilization can be achieved by dynamically assigning priorities on the basis of their current deadlines. A combination of these two scheduling techniques is also discussed.
  @cite_25: Consider the problem of scheduling sporadically-arriving tasks with implicit deadlines using Earliest-Deadline-First (EDF) on a single processor. The system may undergo changes in its operational modes and therefore the characteristics of the task set may change at run-time. We consider a well-established previously published mode-change protocol and we show that if every mode utilizes at most 50 of the processing capacity then all deadlines are met. We also show that there exists a task set that misses a deadline although the utilization exceeds 50 by just an arbitrarily small amount. Finally, we present, for a relevant special case, an exact schedulability test for EDF with mode change.
  @cite_12: IN MANY REAL-TIME APPLICATIONS, THE SET OF TASKS IN THE SYSTEM AS WELL AS THE CHARACTERISTICS OF THE TASKS CHANGE DURING SYSTEM EXECUTION. SPECI- FICALLY, THE SYSTEM MOVES FROM ONE MODE OF EXECUTION TO ANOTHER AS ITS MISSION PROGRESSES. A MODE CHANGE IS CHARACTERIZED BY THE DELETION OF SOME TASKS, ADDITION OF NEW TASKS, OR CHANGES IN THE PARAMETERS OF CERTAIN TASKS, E.G., INCREASING THE SAMPLING RATE TO OBTAIN A MORE ACCURATE RESULT. THIS PAPER DISCUSSES HOW MODE CHANGES CAN BE ACCOMMODATED WITHIN A GIVEN FRAMEWORK OF PRIORITY DRIVEN REAL-TIME SCHEDULING.
summary: A protocol has been introduced by in @cite_12 , assuming Fixed-Task-Priority scheduling. Then, the authors of @cite_25 extended this protocol to the Earliest Deadline First @cite_9 scheduling algorithm.