Deck 5: Real Time Operating Systems and Scheduling Techniques

Question 1

Preemptive, priority based scheduling guarantees ____________

A)hard real time functionality
B)soft real time functionality
C)protection of memory
D)none of the mentioned

Answer 1

soft real time functionality

Question 2

What is Event latency?

A)the amount of time an event takes to occur from when the system started
B)the amount of time from the event occurrence till the system stops
C)the amount of time from event occurrence till the event crashes
D)the amount of time that elapses from when an event occurs to when it is serviced.

Answer 2

the amount of time that elapses from when an event occurs to when it is serviced.

Question 3

Real time systems need to __________ the interrupt latency.

A)minimize
B)maximize
C)not both A &Ber about
D)none of the mentioned

Answer 3

minimize

Question 4

The amount of time required for the scheduling dispatcher to stop one process and start another is known as _____________

A)event latency
B)interrupt latency
C)dispatch latency
D)context switch

Question 5

The most effective technique to keep dispatch latency low is to ____________

A)provide non preemptive kernels
B)provide preemptive kernels
C)make it user programmed
D)run less number of processes at a time

Question 6

Antilock brake systems, flight management systems, pacemakers are examples of

A)safety critical system
B)hard real time system
C)soft real time system
D)safety critical system and hard real time system

Question 7

In real time operating system ____________

A)all processes have the same priority
B)a task must be serviced by its deadline period
C)process scheduling can be done only once
D)kernel is not required

Question 8

In a real time system the computer results ____________

A)must be produced within a specific deadline period
B)may be produced at any time
C)may be correct
D)all of the mentioned

Question 9

. If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.B will have ______ percent of the total processor time.

A)20
B)15
C)50
D)none of the mentioned

Question 10

Earliest deadline first algorithm assigns priorities according to ____________

A)periods
B)deadlines
C)burst times
D)none of the mentioned

Question 11

A process P1 has a period of 50 and a CPU burst of t1 = 25, P2 has a period of 80 and a CPU burst of 35. The total CPU utilization is ____________

A)0.90
B)0.74
C)0.94
D)0.80

Question 12

A process P1 has a period of 50 and a CPU burst of t1 = 25, P2 has a period of 80 and a CPU burst of 35., the priorities of P1 and P2 are?

A)remain the same throughout
B)keep varying from time to time
C)may or may not be change
D)none of the mentioned

Question 13

A process P1 has a period of 50 and a CPU burst of t1 = 25, P2 has a period of 80 and a CPU burst of 35., can the two processes be scheduled using the EDF algorithm without missing their respective deadlines?

A)Yes
B)No
C)Maybe
D)None of the mentioned

Question 14

Using EDF algorithm practically, it is impossible to achieve 100 percent utilization due to __________

A)the cost of context switching
B)interrupt handling
C)power consumption
D)all of the mentioned

Question 15

If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.A will have ______ percent of the total processor time.

A)20
B)15
C)50
D)none of the mentioned

Question 16

If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.C will have ______ percent of the total processor time.

A)20
B)15
C)50
D)none of the mentioned

Question 17

If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.If a new process D requested 30 shares, the admission controller would __________

A)allocate 30 shares to it
B)deny entry to D in the system
C)all of the mentioned
D)none of the mentioned

Question 18

In a safety critical system, incorrect operation ____________

A)does not affect much
B)causes minor problems
C)causes major and serious problems
D)none of the mentioned

Question 19

The amount of memory in a real time system is generally ____________

A)less compared to PCs
B)high compared to PCs
C)same as in PCs
D)they do not have any memory

Question 20

What is the priority of a real time task?

A)must degrade over time
B)must not degrade over time
C)may degrade over time
D)none of the mentioned

Question 21

Memory management units ____________

A)increase the cost of the system
B)increase the power consumption of the system
C)increase the time required to complete an operation
D)all of the mentioned

Question 22

A process P1 has a period of 50 and a CPU burst of t1 = 25, P2 has a period of 80 and a CPU burst of 35. Can the processes be scheduled without missing the deadlines?

A)Yes
B)No
C)Maybe
D)None of the mentioned

Question 23

Type of processor in which single task of a particular application is process is termed as Select one:

A)real time processor
B)dedicated processor
C)applicant processor
D)one task processor

Question 24

Calculate the idle time of the processor with 3 periodic tasks whose execution times are given as 1, 1, and 3, and their periods are 3, 4, and 10. Select one: 17% 12% 88%

A)0.17
B)0.12
C)0.88
D)1

Question 25

In rate monotonic scheduling algorithm Select one:

A)shorter duration job has higher priority,
B)longer duration job has higher priority
C)priority does not depend on the duration of the job
D)none of the mentioned