Real Time (rate monotonic) Scheduling help?

[BlackCat]

Don't know whether anyones familar with rate monotonic and scheduling of real time systems, but here it goes:

 

Task A (Period = 10 msec, CPU time = 2 msec)

Task B (100, 6)

Task C (250, 11)

Task D (500, 5)

Task E (250, 15)

Task F (100, 6)

Task G (500, 5)

Task H (1000, 20)

Task I (2000, 15)

 

Question: During the actual operation of the system the driver may press the brake pedal at most 4 times per second. Pressing the pedal turns the system off. This process requires a worst case of 35 msec of cpu time and must respond within 90msec. Explain how you would incorporate this process into the above model.

 

IS THIS A MATTER OF:- THE 4 TIMES PER SECOND IS THE PERIOD (250msec), BUT IT IS THE DEADLINE OF 35msec THAT THE TASK MUST RESPOND BY SO WE WOULD USE THIS AS THE PERIOD (PERIOD = DEADLINE)?