Determine the Real Time Task is Schedulable using RAM

Determine whether the following set of periodic real time tasks is schedulable on a uniprocessor using RMA. 

Determine the Real Time Task is Schedulable using RAM

Answer: Let us first compute the total CPU utilization achieved due to the given tasks.

Therefore, the necessary condition is satisfied. The sufficiency condition is given by 

Therefore,  Not satisfied.

Although, the given set of tasks fails the Liu and Layland test which is pessimistic in nature, we need to carry out Lehoczkys test. We need to reorder the tasks according to their decreasing priorities.

Testing for task T4: Since e4<= d4,

therefore, T4 would meet its first deadline.

Testing for task T2:

Satisfied.

Task T2 would meet its first deadline.

Testing for task T3: 

Satisfied.

Task T3 would meet its first deadline

Testing for task T1: 

Not satisfied.

Therefore, task T1 would fail to meet its first deadline.

Hence, the given task set is not RMA schedulable.