Question 1

Assume that jobs A-D arrive in the ready queue in quick succession and have the CPU cycle requirements listed below. Using the SRT algorithm, the average turnaround time is ____. Arrival time: 0 1 2 3
Job: A B C D
CPU cycle: 6 3 1 4

Accepted Answer

SRT (Shortest Remaining Time) is a preemptive version of SJF scheduling in which the processor is allocated to the job that has the smallest amount of time remaining to complete.
In this scenario, the first job A has a CPU cycle requirement of 6, which is larger than the other jobs. Therefore, the CPU will be allocated to jobs B, C, and D in the order of their arrival time. 
The SRT algorithm works as follows:
- At time 0, job A arrives in the ready queue with a CPU cycle requirement of 6.
- The CPU is allocated to job B, which has a CPU cycle requirement of 3.
- At time 2, job C arrives in the ready queue with a CPU cycle requirement of 1. Since B has 1 CPU cycle remaining and C has 1 cycle, job C is allocated to the CPU for 1 cycle.
- At time 3, job D arrives in the ready queue with a CPU cycle requirement of 4. Since B has completed its task, D is allocated to the CPU with a CPU cycle requirement of 4.
- Job A is now the only job remaining in the ready queue, and it is allocated the CPU for its remaining 5 cycles.
The turnaround time for each job is calculated as the difference between the completion time and the arrival time. For example, the completion time for job B is 4, and its turnaround time is 4 - 1 = 3. The completion time for job C is 3, and its turnaround time is 3 - 2 = 1. The completion time for job D is 7, and its turnaround time is 7 - 3 = 4. The completion time for job A is 12, and its turnaround time is 12 - 0 = 12. Therefore, the average turnaround time is (3 + 1 + 4 + 12) / 4 = 5. The closest answer choice to this is B (6.25).

Question 2

When selecting the proper time quantum it should be long enough to allow ____ percent of the CPU cycles to run to completion.

Accepted Answer

The time quantum should be long enough to allow a high percentage of the CPU cycles to run to completion. If the time quantum is too short, the CPU spends more time in context switching than in running processes, which decreases overall system performance. Therefore, selecting a time quantum that allows at least 80% of the CPU cycles to run to completion is a good choice.

Question 3

Assume that four jobs A-D require the CPU cycles listed below. Using the SJN algorithm, the average turnaround time is ____. Job: A B C D
CPU cycle: 5 2 6 4

Accepted Answer

The answer of Assume that four jobs A-D require the...

Question 4

____ jobs are treated like all the others once they are in the system.

Accepted Answer

Once a job is in the system, it should be treated with equal priority to all other jobs. All jobs should be prioritized based on their importance and urgency before they are added to the system, but once they are in the system, they should all be treated as high-priority to ensure they are completed in a timely and efficient manner.

Question 5

Assume jobs A-D arrive in quick succession in the READY queue. Using round robin scheduling, the turnaround time for job C is ____. Arrival time: 0 1 2 3
Job: A B C D
CPU cycle: 8 4 9 5

Accepted Answer

The answer of Assume jobs A-D arrive in quick succession...

Question 6

____ allows for faster turnaround of CPU-bound jobs.

Accepted Answer

The answer of ____ allows for faster turnaround of CPU-bound...

Question 7

When the operating system detects a nonrecoverable error, the following step ____, is performed first by the interrupt handler.

Accepted Answer

The answer of When the operating system detects a nonrecoverable...

Question 8

Some systems increase the priority of jobs that have been in the system for an unusually long time to expedite their exit, which is known as ____.

Accepted Answer

This technique is known as aging, where the priority of a job increases with its age to prevent starvation and ensure a fair distribution of resources among all jobs.

Question 9

Internal interrupts, or ____ interrupts, also occur as a direct result of the arithmetic operation or job instruction currently being processed.

Accepted Answer

Internal interrupts that occur as a direct result of the arithmetic operation or job instruction currently being processed are known as synchronous interrupts. Options A, B, and C are not correct as they refer to other types of interrupts.

Question 10

No movement between queues is a very simple policy that rewards those who have ____ jobs.

Accepted Answer

No movement between queues means that once a job is assigned to a queue, it will not move to a different queue. This policy would benefit those with high-priority jobs, as they would be assigned to the high-priority queue and remain there until they are executed, without being displaced by lower priority jobs.

Quiz 4: Processor Management

Assume that jobs A-D arrive in the ready queue in quick succession and have the CPU cycle requirements listed below. Using the SRT algorithm, the average turnaround time is ____. Arrival time: 0 1 2 3 Job: A B C D CPU cycle: 6 3 1 4