intro

Question 1

what is an operating system

Answer 1

this is a software that acts as an interface/ intermediary between the user and the computer hardware

Question 2

what is process scheduling and why is it important in an operating system

Answer 2

this is the process of removing a running process in the CPU and selection of another process in the basis of another strategy.

Question 3

why is process scheduling important

Answer 3

(a) ensures that all resources o the CPU such as time, memory and i/o devices are shared equally among processes
(b) ensures that the computer has a fast response time
(c) ensures that every process is allocated enough time for execution in the CPU
(d) ensures that the CPU is busy that maximizing its utilization

Question 4

define between short term, medium term and long term scheduling

Answer 4

short term scheduling selects the processes that are ready and allocates them to the CPU
long term scheduling determines which process is ready for administration into the system,
medium term removes the process

Question 5

Explain the difference between preemptive and non-preemptive scheduling

Answer 5

preemptive scheduling is a type of scheduling where there can be an interruption during execution while non preemptive scheduling is a type of scheduling where no interruptions are allowed until the execution is done

Question 6

How does the First-Come-First-Serve scheduling algorithm work?

Answer 6

the process that requests the CPU first will be the first one to be executed

Question 7

What are the advantages and disadvantages of FCFS scheduling?

Answer 7

advantages
(a) simple to understand
(b) no starvation

disadvantages
(a) convoy effect
(b)non preemptive
(c) dependence on arrival time

Question 8

Discuss a scenario where FCFS might lead to the “convoy effect.”

Answer 8

if the process with a higher execution time arrives before the process with the lower execution time, that process will have to wait for the process with the longer execution time to be done.

Question 9

Explain the Shortest Job Next (SJN) scheduling algorithm.

Answer 9

this is a type of scheduling where the shortest process with the shortest CPU burst time will be the first to be get in the CPU and be executed

Question 10

What is the main challenge with SJN, and how is it addressed in the Shortest Remaining Time First (SRTF) variant?

Answer 10

the main challenge is it cannot predict the total scheduling time accurately. the SRTF addresses the issue by re evaluating the remaining time for each jobs in the ready queue

Question 11

Discuss the concept of “starvation” in SJF scheduling.

Answer 11

this is a situation where a process is unable to make progress since it keeps on being bypassed by the scheduler in favour of other processes. this happens when a longer process keeps constantly being bypassed by shorter processes by the scheduler

Question 12

How does the Round Robin scheduling algorithm work?

Answer 12

processes are placed in the ready queue where the CPU scheduler goes round allocating the processes in the CPU and giving each process a time slice in which it will be executed

Question 13

Discuss the impact of the time quantum on the performance of Round Robin.

Question 14

Compare Round Robin with FCFS and SJF in terms of turnaround time and response time.

Answer 14

TURNAROUND TIME
in FCFS the turn around time depends on the process arrival therefore the process that arrived first has a lower turnaround time
in SJF the turn around time is lower for the shortest process
in RR it depends with the time quantum, the lower the quantum time the lower the turnaround time
RESPONSE TIME
in FCFS it has a higher response time for the processes that arrive later
in SJF has a lower response time since it prioritizes shorter jobs
in RR the shorter the time quantum the faster the response time

Question 15

Explain the priority scheduling algorithm

Answer 15

the processes are grouped in priority value and the process with the highest priority value is executed first

Question 16

What is the main drawback of basic priority scheduling, and how is it addressed in practice?

Answer 16

potential for priority inversion, a situation where a lower-priority process holds a resource that a higher-priority process needs. This can lead to delays in the execution of the higher-priority process, contrary to the intended priority scheduling policy. Priority inversion can impact system responsiveness and efficiency.

Question 17

Discuss the concept of aging in priority scheduling

Question 18

Describe the concept of multilevel queue scheduling.

Question 19

How are processes classified in a multilevel queue, and how is scheduling performed?

Question 20

What is the purpose of priority levels in a multilevel queue?

Question 21

Explain the multilevel feedback queue scheduling algorithm.

Question 22

How does the system adapt the priority of a process in this algorithm?

Question 23

Discuss the advantages of using feedback queues in scheduling.