Unitwise Questions for Operating System

Questions

UNIT-1

1. Define operating system. Explore the operating system from different viewpoints?
2. Explain the Dual-mode operation of the OS?
3. Explain the concepts of Multiprogramming and Multitasking.
4. Explain the functions of OS w.r.t following.

i)                    Process management  ii) Memory management

5. Explain the different computing environment?
6. What are the tightly coupled systems? What are the advantages?
7. Explain the different special-purpose systems?
8. Explain the different OS operations?
9. Explain the different sets of OS services?
10. Define the following:

i)                    Context switch  ii) Dispatcher  iii) Job scheduling

11. What is a system program, explain its different categories?
12. Explain the Layered Approach of structuring on OS.
13. Define virtual machine with fig. Explain its working.
14.  What are the benefits of a virtual machine?

UNIT-2

1.      What is thread? Explain the different threading models.

2.      What is a process? Explain PCB.

3.      Explain the various scheduling criteria’s.

4.      Explain the different states of a process.

5.      List the different types of Schedulers and differentiate between them.

6.      Define IPC. Explain Message-Passing Systems?

7.      Explain the benefits of using threads?

8.      Consider the following set of process:

Process	Arrival time	Burst time
P1	0	8
P2	1	4
P3	2	9
P4	3	5

i)                    Draw the Gantt chart illustrating the execution of these processes using preemptive SJF.

ii)                  Compute the average waiting time and average turnaround time.

9.      Consider the snap-shot

             

Process	Burst time	Priority
P1	10	3
P2	1	1
P3	2	3
P4	1	4
P5	5	2

i)                    Draw the Gantt charts using

a)      FCFS  b) SJF  c) non preemptive priority 1 has highest priority

d)  RR algorithm. Time Quantum=1ms.

           ii)        Calculate average waiting time and average turnaround time.

iii)                Which of the scheduling algorithm results in the minimal average waiting time?

10.  Write a program using fork ( ) system call to create a process, where parent waits for child to complete its execution.

11.  Explain the concept of thread cancellation.

UNIT-3

1. What is critical section problem? Give its general structure. Explain the requirements that must be satisfied by solution to critical section problem.
2. Give an algorithm for critical section problem involving at least ‘2’ processes satisfying all necessary and sufficient conditions.
3. What is a semaphore? How can it be used to solve mutual exclusion problem? Give a solution to bounded buffer problem using semaphores.
4. With necessary syntax describe the term monitor.
5. Describe the critical section problem.
6. Describe ‘TestAndSet( )’ and ‘ Swap’ instructions of binary semaphore variable.
7. What are the semaphores? Explain two primitive semaphore operations. What are the advantages of semaphores?
8. Explain signal and wait primitive structures of binary semaphore variable.
9. What are monitors, Explain?

UNIT-4

1. Explain how resource allocation graph is used to determine deadlocks?
2. What are the different methods for handling deadlocks? Explain Bonker’s algorithm?
3. “A safe state is not a deadlock state but a deadlock state is an unsafe state”. Explain.
4. What is a deadlock? Explain the four necessary conditions for a deadlock to occur.
5. Explain the different options to recover from a deadlock.
6. Define the terms: safe state and safe sequence. Give an algorithm to find whether or not the system is in safe state.
7. Explain how deadlock can be prevented?
8. What is a wait for graph, how it is used for detecting deadlocks.
9. Draw the Resource Allocation Graph for the following situation. Determine if the system is deadlock,

Given sets P, R & E

P={P1,P2,P3}

R={R1,R2,R3,R4}

E={ P1->R1,P2->R3,R1->P2,R2->P2,R2->P1,R3->P3}

10. Consider the following snap-shot of the system:

	Allocation	Max	Available
	R1  R2  R3  R4	R1  R2  R3  R4	R1  R2  R3  R4
P1	0     0     1      2	0    0     1     2	2     1     0     0
P2	2     0     0      0	2    7     5     0
P3	0     0     3      4	6    6     5     6
P4	2     3     5      4	4    3     5     6
P5	0     3     3      2	0    6     5     2

i)                    Compute the NEED matrix.

ii)                   Is the system in safe state? Justify.

iii)                Can a request (0 1 0 0) from p3 be safely granted.

11. Give deadlock detection algorithm for single and multiple instances of resources.

UNIT-5

1. What is Paging and Swapping?
2. With a neat diagram, discuss the steps involved in handling a page fault.
3. Consider the following page reference string:

7  0  1  2  0  3  0  4  2  3  0   3  2  1  2  0  1  7  0  1

For a memory with three frames. How many page faults would occur for LRU, FIFO and optimal page replacement algorithms? Which is most efficient among them?

4. What do you mean by a address binding? Explain with necessary steps, the binding of instructions and data to memory address.
5. What do you mean by a copy-on-write? Where it is used? Explain in brief.
6. Consider the following page reference string:

1        0  7  1  0  3  1  3  2  0  3  2  4  0  3  2  1  0  7

For a memory with three frames. How many page faults would occur for LRU, FIFO and optimal page replacement algorithms? Which is most efficient among them?

7. Consider the following page reference string:

0        9  0  1  8  1  8  7  8  7  1  2  8  2  7  8  2  3  8  3

For a memory with three frames. How many page faults would occur for LRU, FIFO and optimal page replacement algorithms? Which is most efficient among them?

8. Explain the segmentation memory management. Describe the hardware support required for its implementation.
9. What do you mean by dynamic storage allocation problem? Explain the possible solutions to this problem.
10. Explain the concept of forward-mapped page table.
11. Write a note on Thrashing.
12. On system using demand paged memory it takes 0.12µs to satisfy memory request. If the page is in memory. If the page is not in memory the requesr takes 5000 µs. What would the page fault rate need to be to achieve an effective access time 1000 µs? Assume the system is only running a single process and the CPU is idle during the page swaps.

UNIT-6

1. Explain the following:

i)                    File types  ii) File operations  iii) File attribute

2. Explain the methods for implementing directories.
3. Explain any two file allocation methods with their merits and demerits.
4. What do you mean by free space list? With suitable examples, explain any two methods of implementation of a free space list.
5. What are the major methods used for allocating a disk space? Explain each, with suitable examples.
6. With the help of a neat diagram, describe:

i)                    Tree- structured directory

ii)                  Acyclic-graph directory

7. Explain Virtual File System (VFS).
8. Discuss the directory implementation using:

i)                    Linear list     ii) Hash table

9. What is meant by ‘Consistency Semantics’? Explain the consistency semantics as implemented in a modern O.S.

UNIT- 7

1. Write a note on following:

i)                    SCAN and C-SCAN disk scheduling

ii)                  Disk attachment

2. Describe the access matrix model used for protection purpose in computer system.
3. Explain the following disk scheduling algorithms:

i)                    SSTF    ii) SCAN    iii) LOOK

4. Explain the following:

i)                    Disk management    ii) Swap-space management

5. What are the goals of protection?
6. Explain principles of protection.
7. Suppose the position of cylinder is at 53, sketch the graphical representation for the queue of pending requests in order – 98, 183, 37, 122, 14, 124, 65,67 for FCFS,SSTF and LOOK scheduling schemes. Give your comment on this scenario for above schemes.

UNIT-8

1. What are the components that the kernel module supports under Linux? Explain in detail.
2. What is Linux file system? Explain conflict resolution mechanism of Linux.
3. Explain design principles of Linux system.
4. What are inter process communication facility in Linux.
5. Explain I/O system in Linux.
6. Write short notes on:

i)                    System calls  ii) Processes and Threads   iii) Virtual memory