What is the goal of minimizing response time in process scheduling?
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To shorten the time from when a process is submitted until it starts responding.
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What is the goal of minimizing response time in process scheduling?
To shorten the time from when a process is submitted until it starts responding.
What is non-preemptive scheduling?
A scheduling method where a process cannot be interrupted once it starts executing on the CPU.
How does Non-Preemptive Scheduling handle process execution?
Once a process starts, it runs to completion.
What is one of the main aims of CPU scheduling?
To ensure fairness in allocating CPU time among processes.
What does minimizing turnaround time aim to achieve?
To reduce the total time taken for a process to complete, from submission to completion.
How does CPU scheduling aim to prevent any single process from dominating the CPU?
By allocating CPU time fairly among all processes.
What is used to choose the next process in scheduling?
A scheduling algorithm.
What is the main focus of Process Control Management in Operating Systems?
Managing the execution of processes and their interactions.
What does process scheduling aim to achieve?
To ensure efficient CPU utilization by deciding the order of process execution.
What is the objective of minimizing waiting time in process scheduling?
To decrease the time a process spends waiting in the ready queue before it gets executed.
Which university offers the Process Control Management course?
NSBM Green University.
What is the goal of maximizing CPU utilization?
To keep the CPU busy doing useful work and minimizing idle time.
What is process scheduling?
A mechanism in which an operating system decides which processes run and in what order.
Why is CPU scheduling important?
It optimizes CPU utilization and ensures efficient process management.
Who is the lecturer for the Process Control Management course?
Dr. Pabudi Abeyrathne.
What is pre-emptive scheduling?
A scheduling method where a process can be interrupted and moved to the ready state.
Give an example of a preemptive scheduling algorithm.
Round Robin.
What is the starvation risk in Non-Preemptive Scheduling?
Higher, especially for low priority processes.
What does maximizing CPU utilization aim to achieve?
To ensure the CPU is always busy, doing useful work, and minimizing idle time.
What is a key feature of Preemptive Scheduling regarding process interruption?
Processes can be interrupted.
Why are priorities used in scheduling?
To determine the order in which processes are executed based on their importance.
Can you name examples of preemptive scheduling algorithms?
Round robin, multilevel queues, and multilevel feedback queues.
What is a key characteristic of non-preemptive scheduling algorithms?
Once a process starts executing, it runs to completion without being preempted.
What is a consequence of process switching in Round Robin scheduling?
Process switching requires time; the time quantum clock is already running.
What is an example of a non-preemptive scheduling algorithm?
First Come First Serve (FCFS).
What is the formula to calculate turn-around time (TAT)?
TAT = Tw + Tb.
What type of queue is used to implement Round Robin?
A first in first out (FIFO) queue.
What happens once the CPU has been allocated to a process in FIFO?
The process keeps the CPU until termination or by requesting for I/O.
What is the average waiting time for all processes?
9.6 milliseconds.
Which processes are categorized as low priority in the given scheduling?
P1 and P3.
Which processes are categorized as high priority in the given scheduling?
P2, P4, and P5.
What happens to P1 if a new job arrives in Q1 while it is executing?
P1 will be suspended.
What is the goal of maximizing throughput in process scheduling?
To increase the number of processes that complete their execution in a given period.
When can a non-preemptive process yield the CPU?
Only when it finishes its current CPU burst or voluntarily yields for I/O operations.
Name three preemptive CPU scheduling algorithms.
Round Robin, Shortest Remaining Time First (SRTF), and Priority Scheduling.
What are the types of processes in a Multilevel Queue scheduling?
Interactive Editing Processes, Batch Processes, Student Processes, System Processes, and Interactive Processes.
What is a time slice in scheduling?
A specific amount of CPU time allocated to each queue to schedule its processes, e.g., 80% to foreground in Round Robin and 20% to background in FCFS.
What type of scheduling algorithm is Shortest Remaining Time First (SRT)?
It is a preemptive scheduling algorithm.
What is the role of the CPU scheduler?
To determine the initial process to execute from the ready queue.
Why is scheduling important in an operating system?
It is a fundamental function to ensure that the CPU is not idle.
Which scheduling type is more complex to implement?
Preemptive Scheduling.
Give another example of a non-preemptive scheduling algorithm.
Shortest Job First (SJF).
What does high throughput indicate about a system?
That the system is effectively utilizing its resources to execute and complete processes.
What does CPU burst time represent?
The amount of time a process uses the CPU for a single time.
Can a process use the CPU multiple times before completing its job?
Yes, a process can use the CPU several times before completing the job.
What is the main advantage of preemptive scheduling?
It allows for better responsiveness and resource utilization by enabling higher-priority processes to execute immediately.
What happens if the CPU is free in SJF scheduling?
The next process with the smallest CPU burst time is assigned.
What is the formula for calculating turn-around time (TAT)?
TAT = Tw + Tb
What is the impact of non-preemptive scheduling on response time?
It can lead to longer response times for higher priority processes if they are waiting for lower priority processes to complete.
What are the two types of CPU scheduling?
Pre-emptive scheduling and Non-preemptive scheduling.
What is non-preemptive scheduling?
A scheduling method where a process runs to completion without being interrupted.
What is preemptive scheduling?
A method that allows the operating system to interrupt and suspend a currently running process to start or resume another process.
What happens to a process in non-preemptive scheduling once it starts executing?
It cannot be interrupted until it completes its execution.
What is the difference between preemptive and non-preemptive scheduling?
Preemptive scheduling allows a process to be interrupted and moved to the ready state, while non-preemptive scheduling requires a process to run to completion before another can take over.
What is turnaround time in process scheduling?
The total time taken between the submission of a process for execution and the return of the complete output.
What are the main goals of scheduling algorithms?
To achieve fairness, efficiency, maximize throughput, and minimize turnaround time.
How is the CPU allocated in Priority Scheduling?
To the process with the highest priority.
For what type of systems is Round Robin designed?
Time-sharing systems.
What is defined for each process in Round Robin scheduling?
A time quantum or time slice.
What type of priority may foreground processes have over background processes?
Externally defined priority.
What is a drawback of the FIFO scheduling algorithm?
The average waiting time for FIFO is quite long.
What is the time quantum (TQ) for low priority processes in Multilevel Queue Scheduling?
TQ = 3.
What is the waiting time for Process P2?
2 milliseconds.
What is the main advantage of the Shortest Job First (SJF) algorithm?
It is optimal, providing minimum average waiting time.
What is the turn-around time for Process P3?
13 milliseconds.
What is the turn-around time for Process P4?
14 milliseconds.
What is the waiting time for process P2?
0 milliseconds.
What is the turn-around time for Process P1?
11 milliseconds.
What does burst time refer to in process scheduling?
How long a process actually uses the CPU.
What is the priority of Process P1?
What is the burst time for Process P2?
1 millisecond.
How does context switching in Non-Preemptive Scheduling compare?
Less frequent, resulting in lower overhead.
Give an example of a non-preemptive scheduling algorithm.
First Come First Serve (FCFS).
Why is throughput an important measure?
It is a measure of system efficiency.
What characterizes multilevel queue scheduling?
Processes are permanently assigned to a queue upon entering the system and do not move between queues.
How are equal priority processes scheduled?
Using FIFO (First In, First Out).
How is the ready queue treated in Round Robin?
As a circular queue.
What is the time quantum (TQ) for low priority processes in Multilevel Queue Scheduling?
TQ = 3.
What is the turn-around time for Process P1?
10 milliseconds.
What is the waiting time for process P4?
0 milliseconds.
Which processes are categorized as low priority in the given scheduling?
P1 and P3.
What is the waiting time for process P5?
14 milliseconds.
What does the Gantt Chart represent in this context?
Timings for all processes.
What is the turn-around time for Process P5?
18 milliseconds.
What is the time slice used in the Round Robin scheduling?
2 milliseconds.
What is the burst time for process P3?
2 milliseconds.
What is the burst time for process P3?
2 milliseconds.
What is the frequency of context switching in Preemptive Scheduling?
Frequent, leading to overhead.
What does waiting time refer to in process scheduling?
Average waiting time for processes.
What is fixed priority scheduling?
A method where all processes from the foreground are served before those from the background, which can lead to starvation.
What is non-preemptive scheduling?
A scheduling method where a running process cannot be interrupted and must complete its execution before another process can take over.
What is the distinction between Foreground and Background processes in a Multilevel Queue?
Foreground processes are typically interactive and have higher priority, while Background processes are lower priority.
Can a higher priority process interrupt a lower priority process in non-preemptive scheduling?
No, higher priority processes must wait until the currently running process finishes.
How is the FIFO policy implemented?
It is easily managed with a FIFO queue.
What is the burst time for process P1?
10 milliseconds.
What scheduling algorithm might be used for the foreground queue?
Round Robin (RR) algorithm.
What is a potential downside of preemptive scheduling?
It can lead to increased context switching, which may reduce overall system performance.
What is the turn-around time for Process P2?
1 millisecond.
What is the turn-around time for Process P1?
19 milliseconds.
What is the turn-around time for Process P2?
3 milliseconds.
What is the turn-around time for Process P3?
5 milliseconds.
What is the turn-around time for Process P1?
19 milliseconds.
What are the burst times for the processes P1 to P5?
P1: 10 ms, P2: 1 ms, P3: 2 ms, P4: 1 ms, P5: 5 ms.
What is the burst time for process P2?
1 millisecond.
Give another example of a preemptive scheduling algorithm.
Shortest Remaining Time First (SRTF).
What is turnaround time?
The total time taken from the submission of a process to its completion.
What are examples of Preemptive Scheduling algorithms?
Round Robin (RR), Priority Scheduling (Preemptive).
Can CPU burst time be predicted exactly before a process starts?
No, it cannot be predicted exactly.
What is a characteristic of the average waiting time in Round Robin scheduling?
The average waiting time is usually long.
What does the performance of Round Robin scheduling depend on?
The size of the time quantum (10 – 100 milliseconds).
How do foreground and background processes differ?
They have different response-time requirements and scheduling needs.
What happens if the time quantum is set too short in Round Robin scheduling?
It results in too many process switches, reducing CPU efficiency.
How does preemptive scheduling affect process priority?
Higher-priority processes can preempt lower-priority ones, ensuring critical tasks are completed in a timely manner.
What is a problem associated with the priority scheduling algorithm?
Starvation.
What is the burst time of process P2?
1 millisecond.
What is the turn-around time for Process P2?
19 milliseconds.
What is the turn-around time for Process P3?
13 milliseconds.
What is the turn-around time for Process P4?
2 milliseconds.
What is the turn-around time for Process P5?
19 milliseconds.
What is the waiting time for process P3?
2 milliseconds.
How many times does process P1 execute in the given scheduling?
4 times.
What are the burst times for the processes P1 to P5?
P1: 10 ms, P2: 1 ms, P3: 2 ms, P4: 1 ms, P5: 5 ms.
What is the burst time for process P4?
1 millisecond.
What is throughput in the context of process scheduling?
The number of processes completed in a unit of time.
Which of the three preemptive CPU scheduling algorithms is the easiest to implement?
Round Robin.
In a Multilevel Queue, which type of process has the highest priority?
Interactive Editing Processes.
What is Round Robin?
The oldest, simplest, fairest, and most widely used scheduling algorithm.
What are the two common divisions of processes?
Foreground (interactive) processes and background (batch) processes.
What is the waiting time for process P1?
1 millisecond.
What is the waiting time for process P2?
18 milliseconds.
How is a tie broken when two processes have the same CPU burst time in SJF?
FIFO (First In, First Out) is used to break the tie.
What is the average turn-around time calculated in the Round Robin scheduling?
9.6 milliseconds.
What is the time quantum (TQ) for high priority processes in Multilevel Queue Scheduling?
TQ = 4.
What is the turn-around time for Process P2?
11 milliseconds.
How is throughput often expressed?
As processes per second.
Which algorithm allows processes to move between queues?
Multilevel Queue scheduling algorithm.
Which type of process has the lowest priority in a Multilevel Queue?
Background processes.
What is preemptive scheduling?
A scheduling method where a process can be interrupted and moved to the ready state to allow another process to run.
How does the FIFO scheduling algorithm allocate CPU time?
A process that requests the CPU first is allocated the CPU first.
Can you name a common preemptive scheduling algorithm?
Round Robin is a common preemptive scheduling algorithm.
What is the priority structure in a Multilevel Queue?
Each queue has a priority over lower-level queues.
What is the waiting time for process P3?
11 milliseconds.
What is the average turn-around time calculated in the example?
12.4 milliseconds.
What technique is used to gradually increase the priority of a process?
Aging.
What is the waiting time for process P5?
13 milliseconds.
Do different queues in a multilevel queue system have their own scheduling algorithms?
Yes, each queue has its own scheduling algorithm.
What does the SRTF algorithm do when a new process is added?
It only needs to compare the currently executing processes with those currently waiting to execute.
What is the turn-around time for Process P4?
6 milliseconds.
What is the turn-around time for Process P5?
15 milliseconds.
What is the waiting time for process P5?
4 milliseconds.
What is the burst time for Process P4?
1 millisecond.
Which scheduling type is suitable for real-time systems?
Preemptive Scheduling.
What is CPU burst time?
The assumed duration a process requires the CPU between I/O waits.
What is associated with each process in Priority Scheduling?
A priority level.
How is the ready queue organized in a Multilevel Queue system?
It is separated into several distinct queues.
Why do processes not change queues in multilevel queue scheduling?
Because they do not change their foreground or background nature.
What does a priority level of 0 signify?
It can mean high priority.
Can Priority Scheduling be preemptive or non-preemptive?
Yes, it can be either.
What is the burst time of process P1?
10 milliseconds.
What is the main goal of the Shortest Remaining Time First scheduling algorithm?
To minimize the average waiting time for processes.
What is a potential disadvantage of the SRTF scheduling algorithm?
It has the potential for process starvation.
What is the waiting time for process P1?
9 milliseconds.
What is the average waiting time for all processes?
3.2 milliseconds.
What is the turn-around time for Process P4?
1 millisecond.
What is the average waiting time for all processes?
5.8 milliseconds.
What is the burst time for process P5?
5 milliseconds.
How is the total turn-around time (T T) calculated?
T T = T w + T B.
What is the purpose of CPU scheduling?
To select a process from the ready queue and allocate CPU time.
What are examples of Non-Preemptive Scheduling algorithms?
First-Come, First-Served (FCFS), Priority Scheduling (Non-Preemptive).
What is the First Come First Serve (FIFO/FCFS) scheduling algorithm?
The simplest CPU scheduling non-preemptive algorithm.
What is the basis for scheduling in Shortest Job First (SJF)?
The length of the next CPU burst of a process.
What is unique about the scheduling algorithms in a Multilevel Queue?
Each queue can have its own scheduling algorithm.
What does SRT keep track of during process execution?
It keeps track of the elapsed service time of the running process.
What is the effect of a time quantum that is too long in Round Robin scheduling?
It causes poor response to short interactive requests, resulting in FIFO behavior.
What is the waiting time for process P2?
10 milliseconds.
What is the time slice used in the Round Robin scheduling?
2 milliseconds.
What is the priority relationship between queues in a multilevel queue system?
Each queue has absolute priority over lower-priority queues.
What issue can arise for long processes in the SRTF scheduling algorithm?
Long processes may be held off indefinitely if short processes are continually added.
What is the burst time for process P1?
10 milliseconds.
What is the priority of process P4?
How many processes are represented in the Gantt Chart?
5 processes (P1, P2, P3, P4, P5).
What is the burst time for process P4?
1 millisecond.
What is the burst time for Process P5?
5 milliseconds.
What are the two types of CPU scheduling algorithms?
Preemptive and non-preemptive.
What is the purpose of a Multilevel Queue?
To classify processes into different groups.
What determines the assignment of a process to a specific queue in a Multilevel Queue?
Process priority, size, or process type.
What happens to a running process in SRT if a new process arrives with a shorter estimated run time?
The running process may be preempted.
What is the average turn-around time calculated from the given values?
13.4 milliseconds.
What is a key advantage of the Shortest Remaining Time First (SRTF) scheduling algorithm?
Short processes are handled very quickly.
How can time slices be managed in a Multilevel Queue?
Time slices can be allocated to different queues.
What does Round Robin try to achieve in terms of processing time?
It tries to be fair by equally distributing processing time among all processes.
How does the SRTF algorithm manage system overhead?
It requires very little overhead since it only makes decisions when a process completes or a new process is added.
Which processes are categorized as high priority in the given scheduling?
P2, P4, and P5.
What is the waiting time for Process P5?
10 milliseconds.
What happens to process P1 if a new job arrives in Q1?
P1 will be suspended.
What scheduling algorithm is used in this example?
First Come First Serve (FIFO/FCFS).
What is the burst time for process P2?
1 millisecond.
What is the burst time for Process P3?
2 milliseconds.
How does SRT determine which process to schedule next?
It schedules the process with the smallest remaining time.
What is the formula for calculating turn-around time (TAT)?
TAT = Tw + TB.
What type of scheduling does Multilevel Queue Scheduling use?
Fixed priority scheduling.
What is the waiting time for Process P1?
9 milliseconds.
What is the average turn-around time for the given processes?
7 milliseconds.
What scheduling algorithm is typically used for the background queue?
First Come First Serve (FCFS) algorithm.
What is the waiting time for Process P3?
3 milliseconds.
What is the waiting time for Process P4?
5 milliseconds.
Which scheduling algorithm is being used in this scenario?
Shortest Job First (SJF).
What is the waiting time for process P4?
13 milliseconds.
What is the burst time for process P2?
1 millisecond.
What are the burst times for the processes P1, P2, P3, P4, and P5?
P1: 10 ms, P2: 1 ms, P3: 2 ms, P4: 1 ms, P5: 5 ms.
What is the priority of Process P4?
What is a major difficulty associated with SJF scheduling?
Determining the length of the next process's CPU burst.
What is the time quantum (TQ) for high priority processes in Multilevel Queue Scheduling?
TQ = 4.
What happens when a process uses up its allocated time slice in Round Robin?
It is put at the end of the ready list.
What is the average waiting time for all processes?
8.6 milliseconds.
What is the burst time for process P1?
10 milliseconds.
What is the burst time for process P1?
10 milliseconds.
What is the burst time for process P5?
5 milliseconds.
What is the burst time for Process P1?
10 milliseconds.
What is the turn-around time for Process P3?
4 milliseconds.
What is the turn-around time for Process P5?
9 milliseconds.
What are the burst times for the processes listed?
P1: 10, P2: 1, P3: 2, P4: 1, P5: 5 milliseconds.
What is the burst time of process P5?
5 milliseconds.
What is the waiting time for process P4?
1 millisecond.
What is the burst time for process P5?
5 milliseconds.
