Differentiate between the following by providing a distingui

Differentiate between the following by providing a distinguishable definition for each:

a. Periodic task of a real time system

b. Non-periodic/Aperiodic task of a real time system

c. Sporadic task of a real time system

Solution

Please follow the data and description :

Tasks :

Basically the tasks in the system are said to be fully preemptive and that are used to communicate with the rest of the system via data read at the beginning and written at the end of their executions.

a) Periodic task of a real time system :

In general periodic tasks execute their invocations within the preferred regular time intervals.

For example, let us consider a task T(P) that is characterized by its worst case execution time represented as (w cet), and the period (p) with relative deadline (dl). Now that the k th invocation of T(P) is characterized by its earliest start time (est) and relative deadline (dl). A periodic task with the complex constraints that have been transformed to offline are referred to as an offline task.

b) Aperiodic task of a real time system :

The aperiodic tasks are invoked only once. Their respective arrival times are unknown at the design time.

A aperiodic task for example, T(A) has the arrival time (ar), worst case execution time and relative deadline as the parameters. But when coming to the soft aperiodic tasks, they have no deadline constraints.

c) Sporadic task of a real time system :

These tasks can arrive at the system at arbitrary points or even at the different point in time, but with defined minimum inter-arrival times between two consecutive invocations.

For example let us consider a sporadic task T(S) is characterized by its relative deadline, minimum inter-arrival time and worst case execution time. In this case these attributes are known before the run-time of the system. Parallely the additional information available is its arrival time and its absolute deadline.

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