Operating System

Which of the following is an advantage of using threads?
(i) Increased hardware costs
(ii) Lower throughput
(iii) Efficient utilization of CPU resources
(iv) Increased memory consumption

Which scheduling policy is most suitable for a time shared operating system:

(i) Shortest job first
(ii) Round Robin
(iii) FCFS
(iv) Elevator

Suppose that a process is in BLOCKED state waiting for some I/O service. When the service is completed, it goes to the?
(i) RUNNING state
(ii) READY state
(iii) SUSPENDED state
(iv) TERMINATED state

A process executes the following segment of code:

for (i = 1; i <= n; i++)
fork();

The number of new processes created is:

(i) n
(ii) (n(n+1))/2
(iii) 2^n - 1
(iv) 2^n

Which scheduler selects processes from the ready queue and allocates the CPU?

(i) Long-term scheduler
(ii) Medium-term scheduler
(iii) Short-term scheduler
(iv) Batch scheduler

______ is a technique of improving the priority of process waiting in queue for CPU allocation:

(i) Starvation
(ii) Ageing
(iii) Revocation
(iv) Relocation

Scheduling a process from Ready Queue to CPU is done by
(i) Short Term Scheduler
(ii) Middle Term Scheduler
(iii) Long Term Scheduler
(iv) Dispatcher

Interval between the time of submission and first response to the job is called:

(i) waiting time
(ii) turnaround time
(iii) throughput
(iv) response time

Which type of thread is managed directly by the operating system kernel?

(i) User-level thread
(ii) Kernel-level thread
(iii) Single thread
(iv) Background thread

A process is:

(i) program in high level language kept on disk
(ii) content of main memory
(iii) program in execution
(iv) job in secondary memory

The processes that are residing in main memory and are ready and waiting to execute are kept on a list called

(i) job queue
(ii) ready queue
(iii) execution queue
(iv) process queue

The technique of gradually increasing the priority of a process that wait in a system for a long time is known as?
(i) blocking
(ii) ageing
(iii) starvation
(iv) convoy effect

Which module gives control of the CPU to the process selected by the short-term scheduler?

(i) dispatcher
(ii) scheduler
(iii) Interrupt
(iv) None of these

What is process control block? Explain it.

Discuss the difference among short-term, medium-term and long-term scheduling.

Write a program using "fork" to demonstrate the parent-child relationship of processes.

What do you understand by the term Process in Operating System? Contrast the types of Interprocess Communication models.

What are the two differences between user-level thread and kernel level thread? Under what circumstance is one type better than the other?

Consider the following four processes with following details (time given in ms):

Process	Arrival Time	CPU Burst Time
P1	0	12
P2	0	10
P3	1	4
P4	4	10
P5	2	12

Draw the Gantt chart using RR scheduling with time slice 3ms. Calculate average waiting time and average turn-around time.

Consider the following process :

Process	Arrival Time	Burst Time
P1	0.0	7
P2	2.0	4
P3	4.0	1
P4	5.0	4

Considering non-preemptive and preemptive SJF algorithm, find out average waiting time and average turnaround time in both cases.

Explain the different states of a process during its life cycle using transition diagram.

Describe the fundamental role of "Process Scheduling" in a multiprogramming operating system. Identify and explain at least three scheduling criteria.

What is a Process Control Block? Explain its structure and significance in process management.

Consider the following set of processes with the length of the CPU Burst given in milliseconds:

Process	Burst Time	Priority
A	10	3
B	1	1
C	2	3
D	1	4
E	5	2

The processes are assumed to have arrived in order A, B, C, D, E all at time 0.
Draw the Gantt charts that illustrate the execution of FCFS and SJF scheduling algorithm. Show which algorithm results in the minimum average waiting time.

Define threads and explain their various states. Compare user-level threads with kernel-level threads.

Explain user and kernel level threads in detail.

Discuss multiprocessor scheduling and real-time scheduling techniques.

Explain process state transition diagram of an operating system.

Consider the following CPU processes with arrival times 0 and CPU bursts (in milliseconds) as given below:

Process	Burst time
P1	24
P2	3
P3	3

If the Round Robin Scheduling is used with time quantum of 4 milliseconds to schedule the processes. Draw the Gantt chart and calculate the average waiting time across all processes (in milliseconds).

(a) What is a thread?

(b) How is thread different from a process?

(c) What resources are used when a thread is created?

Describe the objectives of process scheduling. Explain the roles of long-term, medium-term, and short-term schedulers.

Consider the following set of processes with the length of the CPU burst given in milliseconds:

Process	Burst Time	Priority
A	10	3
B	1	1
C	2	3
D	1	4
E	5	2

The processes are assumed to have arrived in order A, B, C, D, E all at time 0. Draw the Gantt charts that illustrate the execution of SJF scheduling algorithm. Show which algorithm results in the minimum average waiting time.

What is thread? Explain the benefits of using thread.

Write a short note on:

Process State transitions

Write short notes on: Process Control Block (PCB)

Write short notes on: Process Control Block