Real-Time Operating Systems

Periodic and aperiodic tasks
¿ Periodic task t i consists of infinite sequence of
identical activities, called instances or job
¿ regularly activated at a constant rate
¿ Activation of first instance of t is called j i
¿ T i = period of the task
¿ Each task t i can be characterized by C i , T i, , D i
• C i , T i, , D i constant for each instance
• In most cases: C i =D i
¿ Aperiodic task J i consists of infinite sequence of
identical activities (instances)
¿ Their activations are not regular
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Periodic and aperiodic tasks:
example
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