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Tuesday, 25 August 2020

IGNOU MCA MCS-041 term-end exam notes,upcoming guess papers,important questions free download

IGNOU MCA MCS-041 4th semester term-end examination (OPERATING SYSTEMS) books/block,term-end exam notes,upcoming guess paper,important questions,study materials,previous year papers download.
IGNOU MCA MCS-041 term-end exam notes,upcoming guess papers,important questions free download

IGNOU BCA/MCA all semester new revised (1st semester,2nd semester,3rd semester,4th semester,5th semester and 6th semester) solved assignments,term-end exam notes,study materials,important questions,books/blocks (June-December) free download.


1. (a) A system contains 10 units of resource R1.The resource requirement of 3 user processes
P1, P2, P3 can be summarised as :
                          P1 P2 P3
Max.                   7   3   5
Requirement       3  2   3
Is the current allocation state feasible and safe ? Apply Banker's algorithm to check it.If a new request of (2, 1, 0) arises, check whether it will be granted or not using Banker's algorithm ?
(b) Discuss the common failures in distributed systems.
(c) Write and explain the Bakery's algorithm to handle the critical section problem for 'n' processes.
(d) Explain the structure of UNIX operating system and its components in brief.

2. (a) Explain FCFS and SSTF disk scheduling algorithms. Calculate the total head movement with the FCFS and SSTF for the following blocks.
50, 91, 150, 92, 130, 18, 140, 70, 60
Initially the head is on block No. 53. Draw the movement diagram also.
(b) Discuss the implementation issues and considerations involved in processing and memory management in multiprocessor operating system.

3. (a) Compare and contrast the architecture of WINDOWS OS with UNIX OS.
(b) Explain what causes the thrashing ? Suggest the mechanism to avoid the thrashing.
(c) With the help of diagrams, explain the concept of demand paging and demand segmentation.

4. (a) Briefly describe the following CPU scheduling algorithms :
(i) FCFS
(ii) RR
(iii) Priority Based Scheduling Explain the difference in the degree to which the above scheduling algorithms discriminate in favour of short processes.
(b) Define mutual exclusion in distributed systems and give an example. Also write and explain the Ricart and Agrawala's mutual exclusion algorithm in distributed systems.

5. (a) Explain the two non-contiguous disk storage allocation schemes with the help of an illustration for each.
(b) Explain the Bell and La Padula Model. Also explain the few components of Information Flow Model.


1. (a) Give solution to Dining Philosophers problem using Monitors.
(b) What is Kernel in OS ? Explain advantages of the micro Kernel approach to OS design compared to monolithic Kernel design approach.
(c) Explain an Access - Matrix model of security with an example.
(d) Explain Lamport's algorithm for ordering of events in a distributed environment with an example.
(e) Explain inter process communication features in Window's 2000 OS.

2. (a) What are different types of multiprocessor operating systems ? Explain any two multiprocessor OS in brief.
(b) Draw the Gantt chart for FCFs and SJF policy, considering the following set of process that arrive at time 0, with the length of CPU time given in milliseconds. Also find the average waiting and average turn arround time.
Process    Processing Time
  P1               05
  P2               04
  P3               06
  P4               02

3. (a) Explain the structure and components of the UNIX operating system in brief.
(b) Explain concept and implementation of  "Working set" model.
(c) Explain Indexed disk storage allocation scheme with an example.

4. (a) Consider the following page reference string :
1, 2, 3, 2, 2, 3, 3, 4,
5, 6, 1, 1, 2, 3, 3.
How many page faults would occur for the following algorithms, assuming 3 frames ?
(i) FIFO Replacement
(ii) LRU Replacement
(iii) Optimal Replacement
(b) List and explain all the design issues involved in Distributed Systems.

5. (a) What is need of mutual exclusion algorithm ? Explain Ricart and Agrawala's mutual exclusion algorithm for distributed operating system.
(b) Explain any two of the following :
(i) Thrashing
(ii) Authentication
(iii) Process scheduling
(iv) I/O management


1. (a) What are the necessary conditions to hold a deadlock in a system ? Explain the Resource Allocation Graph algorithm to deal with deadlock problem. What are the limitations of this approach ?
(b) Consider the set of processes in the given table and the following scheduling algorithms :
(i) FCFS
(ii) Shortest Remaining Time First
(iii) Round Robin (quantum = 2)
Process id  Arrival Time  Execution Time
     A                  0                  4
     B                  2                  7
     C                  3                  3
     D                  4                  2
     E                  6                  5
Draw the Gantt chart and find the average waiting time and average turnaround time for all the above algorithms. Comment on your result. Which one is better and why ?
(c) What is a critical section problem ? List the constraints Dijkstra placed on solutions to the critical section problem.
(d) Consider the following reference string :
1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6.
How many page faults would, occur for the following algorithms, assuming three, five and six frames ?
(i) LRU Replacement
(ii) Optimal Replacement
Remember all frames are initially empty,so first unique pages will all cost one fault each.

2. (a) Describe the following methods for allocating disk space :
(i) Linked Allocation
(ii) Contiguous Allocation
(b) Explain the memory management of Windows 2000 OS.

3. (a) Explain the following with respect to IPC :
(i) Synchronous and Asynchronous Communication
(ii) Need of Buffering and its implementation
(b) Define paging with the help of a diagram.Explain the principles of operation of paging. Also discuss about the H/W support for paging.

4. (a) Differentiate between user thread and kernel thread. What is thread cancellation ? Explain its type. Also explain the various thread models with their relative advantages and disadvantages.
(b) Differentiate between the following :
(i) I/O bound job and CPU bound job
(ii) Multiprocessor scheduling and Uniprocessor scheduling

5. (a) Write short notes on the following :
(i) Temporal and spatial locality of reference
(ii) Memory protection mechanisms
(b) Give an example to explain Lamport's Bakery algorithm in a distributed operating system environment.

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