32 Questions
What is the basis for multiprogrammed operating systems?
CPU scheduling
What is the cycle of process execution involving CPU and I/O wait called?
CPU–I/O Burst Cycle
What is the main concern in the distribution of CPU bursts?
CPU burst distribution
What are the objectives of CPU scheduling?
Introduce CPU scheduling, describe various CPU-scheduling algorithms, discuss evaluation criteria for selecting a CPU-scheduling algorithm, and examine the scheduling algorithms of several operating systems.
What is the purpose of the histogram of CPU-burst Times?
To represent the distribution of CPU bursts
What is the focus of real-time CPU scheduling?
Meeting timing deadlines
What is the role of the short-term scheduler in an operating system?
Selects from among the processes in ready queue and allocates the CPU to one of them.
When does a nonpreemptive scheduling occur?
When a process switches from running to waiting state or terminates.
What is the purpose of the dispatcher in an operating system?
Gives control of the CPU to the process selected by the short-term scheduler.
Define dispatch latency in the context of an operating system.
The time it takes for the dispatcher to stop one process and start another running.
What are the criteria used for CPU scheduling optimization?
Max CPU utilization, max throughput, min turnaround time, min waiting time, min response time.
What is the average waiting time for processes P1, P2, and P3 in FCFS scheduling when the processes arrive in the order P1, P2, P3?
17
In FCFS scheduling, what is the waiting time for processes P1, P2, and P3 when they arrive in the order P2, P3, P1?
3
What is the convoy effect in CPU scheduling?
It refers to the situation where a short process is behind a long process, causing delay for the short process.
What is the purpose of the CPU scheduler in an operating system?
Selects from among the processes in ready queue and allocates the CPU to one of them.
Define the term 'turnaround time' in the context of CPU scheduling.
The amount of time to execute a particular process.
What is the significance of the CPU–I/O Burst Cycle in process execution?
Process execution consists of a cycle of CPU execution and I/O wait.
What is the primary concern regarding the distribution of CPU bursts?
The CPU burst distribution is of main concern.
What is the purpose of introducing CPU scheduling in multiprogrammed operating systems?
To achieve maximum CPU utilization with multiprogramming.
Why is the evaluation of CPU-scheduling algorithms important for selecting a particular system?
To discuss evaluation criteria for selecting a CPU-scheduling algorithm for a particular system.
What is the cycle of process execution involving CPU and I/O wait called?
The CPU–I/O Burst Cycle.
Why is thread scheduling important in the context of operating systems?
To describe various CPU-scheduling algorithms.
What is the purpose of the dispatcher module in an operating system?
The purpose of the dispatcher module is to give control of the CPU to the process selected by the short-term scheduler. It involves switching context, switching to user mode, and jumping to the proper location in the user program to restart that program.
Explain the concept of dispatch latency in the context of an operating system.
Dispatch latency is the time it takes for the dispatcher to stop one process and start another running. It represents the delay in switching the CPU from one process to another.
What are the primary objectives of CPU scheduling in an operating system?
The primary objectives of CPU scheduling are to maximize CPU utilization, increase throughput, minimize turnaround time, reduce waiting time, and minimize response time.
Explain the concept of the convoy effect in the context of CPU scheduling.
The convoy effect refers to the situation where a short process is delayed behind a long process, leading to inefficient use of CPU resources. It is particularly relevant in scenarios involving one CPU-bound and many I/O-bound processes.
What are the optimization criteria used for CPU scheduling algorithms?
The optimization criteria for CPU scheduling algorithms include maximizing CPU utilization, increasing throughput, minimizing turnaround time, reducing waiting time, and minimizing response time.
In First-Come, First-Served (FCFS) scheduling, what is the average waiting time for processes P1, P2, and P3 when the processes arrive in the order P1, P2, P3?
The average waiting time for processes P1, P2, and P3 in FCFS scheduling, when they arrive in the order P1, P2, P3, is 17.
What is the average waiting time for processes P1, P2, and P3 in FCFS scheduling when the processes arrive in the order P2, P3, P1?
The average waiting time for processes P1, P2, and P3 in FCFS scheduling, when they arrive in the order P2, P3, P1, is 3.
Define preemptive scheduling in the context of CPU scheduling.
Preemptive scheduling occurs when the CPU scheduling decisions take place when a process switches from running to ready state or from waiting to ready state. It allows for the interruption of a process's execution to allocate the CPU to another process.
What are the considerations involved in CPU scheduling decisions when a process switches from running to waiting state?
When a process switches from running to waiting state, CPU scheduling decisions must consider access to shared data, preemption while in kernel mode, and interrupts occurring during crucial OS activities.
What is the role of the short-term scheduler in an operating system?
The role of the short-term scheduler is to select from among the processes in the ready queue and allocate the CPU to one of them. It is responsible for making quick decisions to ensure efficient process execution.
Test your knowledge of CPU scheduling concepts, criteria, algorithms, and examples from Chapter 6 of 'Operating System Concepts Essentials – 2nd Edition' by Silberschatz, Galvin, and Gagne. Explore thread scheduling, multiple-processor scheduling, real-time CPU scheduling, and algorithm evaluation.
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