21. Which can increase the number of task switches?
A. time period
B. frequency
C. time rate
D. number of cycles
Answer: A
The time period can be reduced to improve the context switching of the system which will increase the number of task switches.
22. Which mechanism is used behind Windows 3.1?
A. time slice
B. pre-emption
C. cooperative multitasking
D. scheduling algorithm
Answer: C
The cooperative multitasking mechanism has used Windows 3.1 but it does not apply to real-time operating systems.
23. Which of the following provides an illusion of multitasking?
A. the single-task operating system
B. multitasking operating system
C. cooperative multitasking
D. pre-emption
Answer: C
Cooperative multitasking co-operates between them which provides the illusion of multitasking. This is done by periodically executing the tasks.
24. Which task method follows a currently running task to be stopped by a higher priority task?
A. scheduling algorithm
B. time slice
C. cooperative multitasking
D. pre-emption
Answer: D
Pre-emption is an alternative method of the time slice where the currently running task can be stopped or preempted or switched out by a higher priority active task.
25. Which of the following requires programming within the application?
A. time slice
B. scheduling algorithm
C. pre-emption
D. cooperative multitasking
Answer: D
Cooperative multitasking requires programming within the application and the system can be destroyed by a single program that hogs all the processing power. Therefore, it is not applicable in the real-time operating system.
26. What does RMS stand for?
A. rate monotonic scheduling
B. rate machine scheduling
C. rate monotonic software
D. rate machine software
Answer: A
The rate of monotonic scheduling is a method that is used to assign priority for a pre-emptive system such that the correct execution can be guaranteed.
27. Which of the following task swapping method is a better choice in the embedded systems design?
A. RMS
B. pre-emptive
C. cooperative multitasking
D. time slice
Answer: B
The pre-emptive method of task swapping is the first choice for embedded system design because of its better system response.
28. Which of the following allows a lower priority task to run despite the higher priority task being active and waiting to preempt?
A. message queue
B. message passing
C. semaphore
D. priority inversion
Answer: D
The priority inversion mechanism where the lower priority task can continue to run despite there being a higher priority task active and waiting to preempt.
29. What happens to the interrupts in an interrupt service routine?
A. disable interrupt
B. enable interrupts
C. remains unchanged
D. ready state
Answer: A
In the interrupt service routine, all the other interrupts are disabled till the routine completes which can cause a problem if another interrupt is received and held pending. This can result in priority inversion.
30. Which of the following is a part of the RTOS kernel?
A. memory
B. input
C. ISR
D. register
Answer: C
The ISR can send the message for the tasks and it is a part of the RTOS kernel.
