What are the distinguishing characteristics of periodic, aperiodic,  and sporadic real time tasks?

Characteristics of Periodic, Aperiodic and Sporadic Real Time Tasks in Real Time System

Characteristics of Periodic Real Time Task

  1. A periodic task is one that repeats after a certain fixed time interval.
  2. The precise time instants at which periodic tasks recur are usually demarcated by clock interrupts.
  3. For this reason, periodic tasks are also referred to as clock driven tasks.

Characteristics of Sporadic Real Time Task

  1. A sporadic task is one that recurs at random instants.
  2. Each sporadic task is characterized by a parameter gi which implies that two instances of the sporadic task have to be separated by a minimum time of gi.

Characteristics of Aperiodic Real Time Task

  1. An aperiodic task is in many ways similar to a sporadic task.
  2. An aperiodic task can arise at random instants.
  3. In case of aperiodic tasks, the minimum separation gi between two consecutive instances can be 0.
  4. Also, the deadline for aperiodic task is expressed as either an average value or is expressed statistically.