Computer Science Scheduling Algorithms

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Questions and Answers

What is the average turnaround time for the given processes?

6.4 time units

8.2 time units

7.6 time units (correct)

5.8 time units

How is turnaround time calculated?

Turnaround = Completion Time - Burst Time

Turnaround = Completion Time - Arrival Time (correct)

Turnaround = Burst Time + Arrival Time

Turnaround = Arrival Time - Completion Time

Which of the following statements best describes the Shortest Remaining Time First (SRTF) algorithm?

It runs processes based on their arrival sequence only.

It treats all processes equally and runs them in a strict order.

It always allows the longest job to run first.

It chooses the process with the shortest remaining time to run next. (correct)

What happens when a process's quantum expires in a Round-Robin scheduling algorithm?

The process is pre-empted and moved to the end of the ready queue. Signup and view all the answers

Which process has the highest turnaround time based on the given data?

P4 Signup and view all the answers

What is the formula for calculating response time in a scheduling algorithm?

Response Time = Time of First CPU Allocation - Arrival Time Signup and view all the answers

Which is a key characteristic of the Round-Robin scheduling algorithm?

It uses a fixed time quantum for all processes. Signup and view all the answers

In the context of performance metrics, what does a lower average turnaround time indicate?

Processes are completing more quickly. Signup and view all the answers

What is the main principle used in the Round-Robin scheduling algorithm?

First In, First Out (FIFO) principle Signup and view all the answers

A quantum in the Round-Robin scheduling algorithm is defined as what?

The time slice allocated to each process Signup and view all the answers

Which of the following statements about small quantum sizes in Round-Robin scheduling is true?

They can reduce CPU efficiency due to high switching overhead Signup and view all the answers

If a process has a service time of 6 ms and arrives at time 2 ms, how long will the process wait in the Ready Queue after its service starts?

4 ms Signup and view all the answers

What is the average response time for processes that arrive at times 0 ms, 2 ms, and 4 ms with respective service times of 3 ms, 6 ms, and 4 ms?

3 time units Signup and view all the answers

What is the purpose of calculating turnaround time in scheduling algorithms?

To compute the total time taken from arrival to completion Signup and view all the answers

Which performance metric indicates the time from the completion of a process until the next one starts?

Turnaround Time Signup and view all the answers

Which scheduling algorithm focuses on the process with the shortest remaining service time?

Shortest Remaining Time First Signup and view all the answers

Which scheduling type would most likely lead to poor response times?

Large quantum size Signup and view all the answers

In Round-Robin scheduling, how can a larger quantum improve CPU efficiency?

By minimizing overhead from context switching Signup and view all the answers

If Process P1 has a burst time of 4 and arrives at time 0, what is its response time if it starts executing immediately?

0 time units Signup and view all the answers

Which of the following statements is true regarding the Round-Robin scheduling method?

It assigns a fixed time quantum for each process Signup and view all the answers

What is the average turnaround time for the processes given with a set of burst times of 4, 1, 6, 2, 5, and 2, in a Round-Robin schedule?

9 time units Signup and view all the answers

What criteria does the Shortest Remaining Time First scheduling algorithm use to select the next process to execute?

The process with the least amount of burst time remaining Signup and view all the answers

If a process has a burst time of 6 and arrives at time 3, how is its turnaround time affected in a Round-Robin scheduling scenario?

It may increase depending on other processes' execution Signup and view all the answers

How is the average response time calculated across multiple processes?

Total response times divided by the number of processes Signup and view all the answers

Study Notes

Shortest Remaining Time First Algorithm

The shortest remaining time first algorithm is a preemptive scheduling algorithm which selects the job with the smallest remaining burst (or service) time.
The algorithm is efficient as it provides the lowest average waiting time.
Performance Metrics:
- Turnaround Time: The difference between completion time and the arrival time of a process; it is the amount of time a process is in the system.
- Average Turnaround: The average time it takes for a process to complete.

Round-Robin Algorithm

The Round-Robin algorithm is a scheduling algorithm that assigns equal time intervals to each process, known as quantum.
This algorithm uses preemption based on a clock.
The algorithm runs in the following situations:
- When the currently running process is finished.
- When the CPU is available.
- When the quantum for the running process has expired.
If a process is not finished after its quantum, it is added to the end of the ready queue and waits to run again.

Round-Robin Algorithm Performance Metrics

Response Time: This is the amount of time it takes for a process to start execution after it arrives in the system.
Average Response Time: This is the average time it takes for a process to start after arriving.
Turnaround Time: Similar to the SRTF algorithm, this is the time it takes for a process to compete.
Average Turnaround Time: The average time it takes for all processes to complete.

Exercises

Exercise 1:
- The exercise requires the user to simulate CPU scheduling using SRTF and Round Robin algorithms as well as calculate turnaround and response time for six processes.
Exercise 2:
- The exercise requires the user to simulate CPU scheduling using SRTF and Round Robin algorithms as well as calculate turnaround and response time for three processes.

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Description

This quiz covers essential scheduling algorithms in computer science, focusing on the Shortest Remaining Time First and Round-Robin methods. It explores their efficiency, turnaround times, and performance metrics. Test your understanding of these crucial concepts in process management!