CODEWITHSUNDEEP
real-timereal-time-systems
Nicooost
Nicooost

Reputation: 76

What happens when a realtime system violates its hard time target?

I know the system goes into some kind of emergency mode when it times out and the exception is then handled, but what part of the system makes the system go into this mode?

Thanks!

Upvotes: 0

Views: 66

Answers (1)

E. Douglas Jensen
E. Douglas Jensen

Reputation: 531

You are assuming a "hard" real-time system. There are two major classes: the rare class of RTOSs that directly support deadline-based scheduling, and the ordinary class of RTOSs that do not and thus map deadlines onto the RTOS native priorities. Deadline miss(es) are detected somewhat differently in these two classes.

Assuming that the task set was evaluated in advance as feasible, then at least one task missing its deadline will be detected by the RTOS, and the exception will be handled. It is possible that despite being a "hard" real-time system, in some cases various other constraint violations (e.g., resource use or dependency, etc.) might be possible and will/should be detected by the RTOS. The details differ among different RTOS's.

Upvotes: 0

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