Real-Time Systems

2

Real-Time Task Scheduling

In the last chapter we defined a real-time task as one that has some constraints associated with it. Out of the three broad classes of time constraints we discussed, deadline constraint on tasks is the most common. In all subsequent discussions we, therefore, implicitly assume only deadline constraints on real-time tasks, unless we mention otherwise.

Real-time tasks get generated in response to some events that may either be external or internal to the system. For example, a task might get generated due to an internal event such as a clock interrupt occurring every few milliseconds to periodically poll the temperature of a chemical plant. Another task might get generated due to an external event such as the user pressing ...