Engineering Questions with Answers - Multiple Choice Questions
MCQs on Embedded Operating System, Middleware and Scheduling
1 - Question
MCQs on Prediction of Execution Times
Identify the standard software components that can be reused?
a) application manager
b) operating system
c) application software
d) memory
View Answer
Explanation: There are certain software components that can be reused in an embedded system design. These are the operating systems, real-time databases and some other forms of middleware.
2 - Question
What does WCTE stand for?
a) wait case execution time
b) wait case encoder time
c) worst case execution time
d) worst code execution time
View Answer
Explanation: The WCTE is the worst case execution time which is an upper bound on the execution times of task. It can be computed for certain programs like while loops, programs without recursion, iteration count etc.
3 - Question
For which of the following WCET can be computed?
a) C program
b) assembly language
c) VHDL
d) program without recursion
View Answer
Explanation: The WCET computing is a difficult task for assembly language and for computing WCTE for any high-level language without the knowledge of the generated assembly code is impossible. advertisement
4 - Question
The WCET of which component can be computed if the task is mapped to hardware?
a) hardware
b) task
c) both task and hardware
d) application manager
View Answer
Explanation: The worst case execution time of the hardware can be computed if the task is mapped to the hardware which in turn requires the synthesis of the hardware.
5 - Question
Which estimation approach is used by Jha and Dutt for hardware?
a) accurate cost and performance value
b) estimated cost and performance value
c) performance value
d) accurate cost
View Answer
Explanation: There are different estimation techniques used. One such is the estimated cost and performance value which is proposed by Jha and Dutt for hardware. The accurate cost and performance value is proposed by Jain et al for software.
6 - Question
Which estimate approach is more precise?
a) estimated cost and performance value
b) accurate cost and performance value
c) performance value and execution time d) estimated cost
View Answer
Explanation: The accurate cost and performance value is possible if interfaces to software synthesis tools and hardware synthesis tools exist and is more precise than any other methods.
7 - Question
Which estimate approach takes more time to consume?
a) accurate value
b) estimated value
c) accurate cost and performance value
d) estimated cost and performance value
View Answer
Explanation: The accurate cost and the performance value method is time-consuming but the other estimating approaches are less time consuming.
8 - Question
Which estimation technique can be used if interfaces to software synthesis tools and hardware synthesis tools exist?
a) performance value
b) estimated cost
c) estimated cost and performance value
d) accurate cost and performance value
View Answer
Explanation: The accurate cost and performance value is possible if interfaces to software synthesis tools and hardware synthesis tools exist.
9 - Question
Which of the following is the base for scheduling algorithm?
a) WCET
b) time
c) execution time
d) address accessing time
View Answer
Explanation: The base for scheduling algorithm is the WCET, worst case execution time which is a bound on the execution time of tasks. Such computing is undecidable in the general case, so it is decidable for certain programs only such as programs without recursion, iteration count, while loops etc.
10 - Question
MCQs on Classification of Scheduling Algorithms
Which classification is based on the extension to standard operating systems?
a) software and hardware deadline
b) aperiodic deadline
c) periodic deadline
d) static and dynamic deadline
View Answer
Explanation: The real-time scheduling can be classified into various criteria. The fundamental classification is the software and hardware deadline which is based on the extension to standard operating systems.
11 - Question
Which of the following defines the task which must be executed at every defined unit of time?
a) aperiodic task
b) periodic task
c) job
d) process
View Answer
Explanation: The periodic task is the one which must be executed in a defined unit of time say ‘p’ where p is called the period.
12 - Question
Which of the task are not periodic?
a) periodic task
b) unpredictable task
c) aperiodic task
d) job
View Answer
Explanation: The aperiodic task is the one in which the task is not periodic but the periodic task is the one in which are the task are periodic. Each execution of a periodic task is known as the job. advertisement
13 - Question
Which of the following is an aperiodic task requesting the processor at unpredictable times?
a) job
b) aperiodic task
c) sporadic
d) periodic task
View Answer
Explanation: The aperiodic tasks request the processor at unpredictable times if and only if there is a minimum separation between the times at which they request the processor which is called sporadic.
14 - Question
Which of the scheduling algorithm are based on the assumption that tasks are executed until they are done?
a) periodic task
b) aperiodic task
c) non-preemptive scheduling
d) preemptive scheduling
View Answer
Explanation: The nonpreemptive scheduling is based on the assumptions that the tasks are executed until the task is done whereas the preemptive scheduling is used if the task has long execution times or for a short response time.
15 - Question
Which of the following schedulers take decisions at run-time?
a) preemptive scheduler
b) non preemptive scheduler
c) dynamic scheduler
d) static scheduler
View Answer
Explanation: The dynamic schedulers take decisions at run-time and they are quite flexible but generate overhead at run-time whereas static scheduler is the ones in which the scheduler take their designs at the design time.
16 - Question
Which scheduler takes their designs at design time?
a) preemptive scheduler
b) non preemptive scheduler
c) dynamic scheduler
d) static scheduler
View Answer
Explanation: The static scheduler take their designs at the design time and it also generates tables of start times which are forwarded to a simple dispatcher but the dynamic scheduler takes a decision at the run-time.
17 - Question
Which scheduler generates tables and forward to the dispatcher?
a) static scheduler
b) dynamic scheduler
c) aperiodic scheduler
d) preemptive scheduler
View Answer
Explanation: The static scheduler generates tables of start times which are forwarded to a simple dispatcher and it can be controlled by a timer which makes the dispatcher analyze the table.
18 - Question
Which of the following systems are entirely controlled by the timer?
a) voltage triggered
b) time triggered
c) aperiodic task scheduler
d) periodic task scheduler
View Answer
Explanation: The systems which are entirely controlled by a timer are known as entirely time-triggered systems. A temporal control structure is associated with the entirely time-triggered system which is encoded in a TDL, task descriptor list.
19 - Question
What does TDL stand for?
a) task descriptor list
b) task design list
c) temporal descriptor list
d) temporal design list
View Answer
Explanation: TDL is a task descriptor list which contains the cyclic schedule for all activities of the node and the temporal control structure is encoded by the task descriptor table.
20 - Question
Which scheduling algorithm can be used in mixed software/hardware systems?
a) simple algorithm
b) complex algorithm
c) uniprocessor algorithm
d) multiprocessor algorithm
View Answer
Explanation: The complex algorithm is used in mixed software/hardware systems. It can be used to handle multiple processors.
21 - Question
Which algorithm can distinguish homogeneous multiprocessor system and heterogeneous multiprocessor system?
a) complex algorithm
b) simple algorithm
c) scheduler algorithm
d) preemptive algorithm
View Answer
Explanation: The simple algorithm can be used in handling single processors and the complex algorithm is used in mixed both in software and the hardware systems. It can also be used to distinguish homogeneous multiprocessor system and heterogeneous multiprocessor systems. The complex algorithm can be used to handle multiple processors whereas.
22 - Question
Which of the following scheduling test can be used to show that no scheduling exist?
a) sufficient test
b) necessary test
c) complex test
d) simple test
View Answer
Explanation: The necessary and sufficient conditions are used in the schedulability test. For necessary condition, the test is based only on the necessary conditions and it also can be used to show that no schedule exists. The sufficient condition indicates that no schedule exists even if there exists one.
23 - Question
Which scheduling test is used to indicate that no scheduling exist even if there exist one?
a) complex test
b) simple test
c) sufficient test
d) necessary test
View Answer
Explanation: The sufficient condition indicates that no schedule exists even if there exist one and the necessary condition indicates that no schedule exists even if a schedule exists.
24 - Question
Which algorithm can be used to schedule tasks at run-time?
a) online scheduler
b) offline scheduler
c) multiprocessor scheduler
d) uniprocessor scheduler
View Answer
Explanation: The online scheduling algorithm schedule tasks at run-time which is based on the information regarding the task whereas offline algorithms schedule tasks take a priori knowledge about the execution times, arrival times and deadlines into account.
25 - Question
MCQs on Aperiodic Scheduling
Which algorithm is based on Jackson’s rule?
a) EDD
b) LL
c) EDF
d) LST
View Answer
Explanation: The EDD or earliest due date is based on Jackson’s rule. The Jackson’s rule states that for a given a set of n independent tasks, any algorithm that executes the tasks in the order of nondecreasing deadlines is optimal with respect to reducing the maximum lateness. EDF is the earliest deadline first, LL is the least laxity and the LST is the least slack time first.
26 - Question
What does EDD stand for?
a) earliest device date
b) earliest due date
c) earliest device deadline
d) earliest deadline device
View Answer
Explanation: The earliest due date requires all tasks to be sorted by their deadlines and it is based on Jackson’s rule. If the deadlines are known, EDD algorithm can be used.
27 - Question
Which of the following can be implemented as static scheduling algorithm?
a) EDF
b) LL
c) EDD
d) LST
View Answer
Explanation: The EDD can be implemented as static scheduling algorithm if the deadlines are known in advance and it follows Jackson’s rule. advertisement
28 - Question
What does EDF stand for?
a) earliest deadline fix
b) earliest due fix
c) earliest due first
d) earliest deadline first
View Answer
Explanation: The EDF stands for earliest deadline first. This algorithm is optimal with respect to minimizing the maximum lateness and is implemented as dynamic scheduling algorithm for a set of n independent tasks with arbitrary arrival times, any algorithm that at any instant executes the task with the earliest absolute deadline among all the ready tasks is optimal with respect to minimizing the maximum lateness.
29 - Question
Which algorithm is dynamic scheduling algorithm?
a) LL
b) LST
c) EDF
d) EDD
View Answer
Explanation: The EDF or earliest deadline first can be implemented as a dynamic scheduling algorithm.
30 - Question
In which scheduling, the task priorities are a monotonically decreasing function of laxity?
a) LL
b) EDD
c) EFD
d) LST
View Answer
Explanation: In the least laxity algorithm, the laxity can be changed dynamically which shows that the task priorities are a monotonically decreasing function of laxity.
31 - Question
Which scheduling algorithm is an optimal scheduling policy for mono-processor system?
a) preemptive algorithm
b) LST
c) EDD
d) LL
View Answer
Explanation: The least laxity algorithm is a dynamic scheduling algorithm and hence it can be implemented as an optimal scheduling policy for the mono-processor system. The LL scheduling algorithm is also preemptive scheduling.
32 - Question
Which scheduling algorithm cannot be used with a standard OS providing fixed priorities?
a) LL
b) LST
c) EDD
d) EFD
View Answer
Explanation: The least laxity algorithm cannot be used with a standard OS providing fixed priorities because of its dynamic property.
33 - Question
Who proposed the LDF algorithm?
a) Bayes
b) Nyquist
c) Lawler
d) Stankovic
View Answer
Explanation: The latest deadline first or LDF is proposed by Lawler which performs a topological sort. It is based on the total order compatible with the partial order with respect to the task graph.
34 - Question
What does LDF stand for?
a) last deadline first
b) least deadline first
c) list deadline first
d) latest deadline first
View Answer
Explanation: The LDF or latest deadline first is a scheduling algorithm which is proposed by Lawler.
35 - Question
Which algorithm is non-preemptive and can be used with a mono processor?
a) LDF
b) pre-emptive
c) aperiodic
d) LL
View Answer
Explanation: The latest deadline first or LDF is a non-preemptive scheduling algorithm and can be used with a mono processor whereas LL or least laxity is a preemptive scheduling algorithm.
36 - Question
Which algorithm requires the periodic checks of the laxity?
a) LST
b) LL
c) EDD
d) EFD
View Answer
Explanation: The LL scheduling algorithm requires the knowledge of the execution times and the periodic check of the laxity.
37 - Question
Who developed the heuristic algorithm?
a) Stankovic and Ramamritham
b) Stankovic and Lawler
c) Lawler
d) Stankovic
View Answer
Explanation: The heuristic algorithm is developed by Stankovic and Ramamritham in 1991.
38 - Question
Which algorithm can be used if the preemptive is not allowed?
a) heuristic algorithm
b) LL
c) EDD
d) LST
View Answer
Explanation: The heuristic algorithm was proposed by Stankovic and Ramamritham in 1991 can be used if the preemption is not allowed.
39 - Question
Deadline interval – execution time =
a) laxity
b) execution time
c) deadline interval
d) period
View Answer
Explanation: The laxity is defined as the deadline interval minus the execution time. It is also known as the slack.
40 - Question
MCQs on Periodic Scheduling
The execution of the task is known as
a) process
b) job
c) task
d) thread
View Answer
Explanation: The execution of the task is known as the job. The time for both the execution of the task and the corresponding job is same.
41 - Question
Which scheduling algorithm is can be used for an independent periodic process?
a) EDD
b) LL
c) LST
d) RMS
View Answer
Explanation: The RMS os rate monotonic scheduling is periodic scheduling algorithm but EDD, LL, and LST are aperiodic scheduling algorithm.
42 - Question
What is the relationship between the priority of task and their period in RMS?
a) decreases
b) increases
c) remains unchanged
d) linear
View Answer
Explanation: The priority of the task decreases monotonically with respect to their period in the rate monotonic scheduling, that is, the task with the long period will get a low priority but task with the short period will get a high priority. advertisement
43 - Question
Which of the following uses a preemptive periodic scheduling algorithm?
a) Pre-emptive scheduling
b) RMS
c) LL
d) LST
View Answer
Explanation: The rate monotonic scheduling is a periodic scheduler algorithm which follows a preemptive algorithm. LL is also preemptive scheduling but it is aperiodic scheduling algorithm.
44 - Question
Which of the following is based on static priorities?
a) Periodic EDF
b) RMS
c) LL
d) Aperiodic EDF
View Answer
Explanation: The rate monotonic scheduling is a periodic scheduler algorithm which follows a preemptive algorithm and have static priorities. EDF and LL have dynamic priorities.
45 - Question
How many assumptions have to meet for a rate monotonic scheduling?
a) 3
b) 4
c) 5
d) 6
View Answer
Explanation: The rate monotonic scheduling has to meet six assumptions. These are: All the tasks should be periodic, all the tasks must be independent, the deadline should be equal to the period for all tasks, the execution time must be constant, the time required for the context switching must be negligible, it should hold the accumulation utilization equation.
46 - Question
Which of the following can be applied to periodic scheduling?
a) EDF
b) LL
c) LST
d) EDD
View Answer
Explanation: The earliest deadline first can be applied both to the periodic and aperiodic scheduling algorithm. But LL, LST, and EDD are aperiodic scheduling. It is not applicable to the periodic scheduling.
47 - Question
Which of the following periodic scheduling is dynamic?
a) RMS
b) EDF
c) LST
d) LL
View Answer
Explanation: The EDF or the earliest deadline first is a periodic scheduling algorithm which is dynamic but RMS or rate monotonic scheduling is the periodic algorithm which is static. The LL and LST are aperiodic scheduling algorithm.
48 - Question
Which of the following do the sporadic events are connected?
a) Interrupts
b) NMI
c) Software interrupt
d) Timer
View Answer
Explanation: The sporadic events are connected to the interrupts thereby execute them immediately as possible since the interrupt priority is the highest in the system.
49 - Question
Which of the following can execute quickly, if the interrupt priority is higher in the system?
a) EDD
b) Sporadic event
c) LL
d) Aperiodic scheduling
View Answer
Explanation: The sporadic events are connected to the interrupts and execute them immediately because the interrupt priority is the highest priority level in the system.
50 - Question
Which of the following are used to execute at regular intervals and check for ready sporadic tasks?
a) sporadic task server
b) sporadic task client
c) sporadic event application
d) sporadic register
View Answer
Explanation: The special sporadic task servers are used that execute at regular intervals and check for ready sporadic tasks which improve the predictability of the whole system.
51 - Question
How is a sporadic task can turn into a periodic task?
a) scheduling algorithm
b) sporadic task event
c) sporadic register
d) sporadic task server
View Answer
Explanation: The special sporadic task servers execute at regular intervals and check for ready sporadic tasks and by this, sporadic tasks are essentially turned into periodic tasks which can improve the predictability of the whole system.
52 - Question
Which of the following is more difficult than the scheduling independent task?
a) scheduling algorithm
b) scheduling independent task
c) scheduling dependent task
d) aperiodic scheduling algorithm
View Answer
Explanation: The scheduling dependent task is more difficult than the independent scheduling task. The problem of deciding whether or not a schedule exists for a given set of dependent tasks and a given deadline is NP-complete.
53 - Question
Which scheduling is the basis for a number of formal proofs of schedulability?
a) LL
b) RMS
c) LST
d) EDD
View Answer
Explanation: The rate monotonic scheduling which is an independent scheduling algorithm form the basis for a number of formal proofs of schedulability.
54 - Question
Which of the following is independent scheduling?
a) LL
b) LST
c) EDD
d) RMS
View Answer
Explanation: The RMS or rate monotonic scheduling is the independent scheduling algorithm which is included in the assumptions of RMS, that is, all tasks should be independent.