mca operating system 2006-2013

(Please Write your Exam Roll No. immediately) Exam. Roll No. ..

END-TERM EXAMINATION DECEMBER 2006

Time: 3 Hours Maximum Marks: 75

Q. 1. (a) What is an interrupt? (b) What are the distinctions between internal and external

fragmentation? (c) List three advantages of user level threads over kernel level threads. (d) What is monitor? (e) What are the differences among deadlock avoidance, detection and

prevention? (f) What are the differences between SCAN and C-SCAN disk

scheduling algorithms? (g) What is a file control block? (h) What are different file attributes and file operations in a typical file

system. (8 x 2.5 = 20)

UNIT - I Q. 2.

(a) Why are segmentation and paging sometimes combined into one scheme? Compare paging with segmentation with respect to amount of memory translation structures in order to convert virtual addresses to physical addresses. (6)

(b) Consider a simple segmentation system that has the following segment table. (4)

Starting Address Length (bytes) 660 248 1752 422 222 198 996 604

For each of the following logical addresses, determine the physical address or indicate if a segment fault occurs:

(i) 0, 198 (i) 2, 156 (i) 1, 530 (i) 3, 444

Exam Series Code: 100353DEC06200382 Subject: Operating System

Note: Q.1 is compulsory and attempt four from Question No. 2 to 9 selecting one question from each unit

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Q. 3. (a) A process contains eight virtual pages on disk and is assigned a fixed

allocation of four page frames in main memory. The following page trace occurs

1,0,2,2,1,7,6,7,0,1,2,0,3,0,4,5,1,5,2,4,5,6,7,6,7,2,4,2,7,3,3,2,3

Show the successive page residing in the four frames using LRU replacement policy. Compare the hit ratio in main memory. (4)

(b) Discuss the hardware support required to support demand paging? Why is the principle of locality crucial to the use of virtual memory?

(6) UNIT-II

Q. 4. (a) What are the issues related to multithreading environment? (5)

(b) Consider the following set of processes. (5)

Process Name Arrival Time Processing Time A 0 3 B 1 5 C 3 2 D 9 5 E 12 5

Calculate the average waiting time and average turnaround time for FCFS, Round Robin (Time slice=2) and shortest job first scheduling algorithms.

Q. 5. (a) What are the conditions generally associated with reader-writer

problem? (5)

(b) Show that Petersons solution to critical section problem satisfies all the requirements of critical section solutions. (5)

UNIT III

Q. 6. (a) Explain the methods for deadlock prevention.

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(b) Consider the following snapshot of system:

Allocation Max Available A B C D A B C D A B C D

P0 0 0 1 2 0 0 1 2 1 5 2 0 P1 1 0 0 0 1 7 5 0 P2 1 3 5 4 2 3 5 6 P3 0 6 3 2 0 6 5 2 P4 0 0 1 4 0 6 5 6

Answer the following question using the Bankers algorithm: (i) What is the content of Need Matrix? (ii) Is system in a safe state? (iii) If a request from process P1 arrives for (0, 4, 2, 0) can the request be

granted immediately.

Q. 7. (a) What is the Disk Structure? What are different Disk Management Methods? (5)

(b) Explain RAID Structure. (5)

UNIT - IV

Q. 8. (a) List the advantages and disadvantages of sequential file access method and direct access method (or Relative access method) (5)

(b) Compare the different directory structure implementation in a file system. (5)

Q. 9. (a) Explain the disk allocation methods for a file system giving the efficiencies of each. (5)

(b) How free space is managed in a file system. (5)

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END-TERM EXAMINATION Third Semester [MCA] - DECEMBER 2005


Q. 1. (a) What are the difference between trap and interrupt? (b) What is the purpose of base and limit registers? (c) What is the purpose of command interpreter? (d) Difference between system calls and system programs. (e) What is the difference between user level and kernel level threads? (f) Define the difference between pre-emptive and non pre-emptive

scheduling? (g) Is it possible to have a deadlock involving only one single process? Explain. (h) What do you mean by memory fragmentation?

8 x 2.5 = 20 UNIT - I

Q. 2. (a) What is paging? How it differs from segmentation? Explain a system which uses a combined scheme of segmentation with paging. 6

(b) Consider a paging system with the page table stored in memory. If a memory reference takes 200 nano secs and 80 percent of all page table references are found in the associative registers, what is the effective memory reference time? (Assume associative register references time as zero). 4

Q. 3. (a) Consider the following page reference string:- 6 1, 5, 2, 3, 2, 1, 4, 2, 3, 5, 1, 2, 5, 4, 3, 2, 4, 1, 2

How many page faults will occur assuming three frames for (i) LRV (ii) FIFO and (iii) Optimal Replacement

(b) Describe the steps how a page fault is handled by the operating system. 4

UNIT II

Q. 4. (a) What are the necessary conditions for a deadlock to occur? Explain. 5 (b) Explain Bankers algorithm for deadlock avoidance. 5

Q. 5. (a) What are semaphores? How these are implemented? 4

Paper Code: MCA 201 Subject: Operating System

Note: Attempt any five questions. All questions carry equal marks.

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(b) Explain with examples the following scheduling algorithm. 6 (i) FCFS (ii) SJF (iii) Round Robin

UNIT - III

Q. 6. Suppose a disk queue with requests for I/O to blocks on cylinders:- 10 100, 175, 50, 120, 120, 20, 150, 75, 200

If the disk head is currently at 60, find out the total disk head movement for the following algorithm:-

(a) FCFS (b) SSTP (c) SCAN (d) LOOK (e) C-SCAN

Q. 7. (a) How swap space is managed by the Operating system? Explain. 5

(b) What are interrupt? How interrupt are handled by the operating system? 5

UNIT - IV

Q. 8. Explain the contiguous, linked and indexed file allocation techniques with suitable example. What technique is used in Unix Operating System? 10

Q. 9. (a) What are the different file access methods? 5 (b) Explain the different directory structure? 5

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Q. 1. (a) What are the different functionalities of an operating system? Explain. 6

(b) How protection is provided by the operating system at the file system level? Explain different protection mechanism. 6

Q. 2. (a) What is a process? How it differs from a program? Differentiate between a multiprocessing system and a multiprocessor system. 6

(b) Explain the purpose of schedulers. With a neat diagram explain different types of schedulers. 6

Q. 3. (a) What is a directory? Explain different directory structure. 6

(b)Explain the linked and indexed memory allocation technique for secondary storage management. How file space is allocated in Unix Operating system?

6 Q. 4. (a) Differentiate between buffering and spooling. 4

(b) Explain pages segmentation memory management technique. What special hardware are required for such a system? 8

Q. 5. (a) What is deadlock? Explain four necessary conditions for a deadlock to occur. 6

(b) What is thrashing? Why is it required? 6

Q. 6. (a) What do you mean by fragmentation? How the fragmentation problem can be solved? 6

(b) What is device controller? State some advantages of placing functionality in a device controller rather than in the kernel. 6

Q. 7. (a) What are the various algorithms for process scheduling? Explain each of them. 8

(b) What are concurrent and cooperating processes? Explain. 4


Note: Attempt any five questions. All questions carry equal marks.

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Q. 8. Write short notes on each of the following :- 12 (a) Segmentation (b) Page Fault (c) Virtual Memory

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Q. 1. (a) Define the essential properties of the following types of Operating Systems:- 6

(i) Batch (ii) Interactive (iii) Time Sharing (iv) Real Time (v) Network (vi) Distributed

(b) What are the differences between a trap and an interrupt? What is the use of each function? 6

Q. 2. (a) Describe the actions taken by a thread library to context switch between user-level threads. 6

(b) Describe the differences among short-term, medium-term and long-term scheduling. 6

Q. 3. Consider the following set of process, with the length of the CPU burst time given in milliseconds 12

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

The process are assumed to have arrived in the order P1,P2, P3, P4,P5 all at time 0.

(a) Draw four Gantt charts that illustrate the execution of these processes using FCFS, SJF, A non preemptive priority and RR (quantum=1) scheduling.

(b) What is the turnaround time of each process for each of the scheduling algorithm in part (a)?

(c) What is the waiting time of each process for each of the scheduling algorithm in part (a)?


Note: Attempt any five questions.

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(d) Which of the schedules in part (a) results in the minimal average waiting time (over all process)?

Q. 4. (a) Describe the following allocation algorithms:- 6 (i) First Fit (ii) Best Fit (iii) Worst Fit

(b) Consider a logical address space of eight pages of 1024 words each, mapped onto a physical memory of 32 frames. 6

i. How many bits are there in the logical address? ii. How many bits are there in the physical address?

Q. 5. Consider the following page reference string:- 12 1, 2, 3, 4, 2, 1, 5, 6, 1, 2, 2, 3, 7, 6, 3, 2, 1, 2, 3, 6

How many page faults would occur for the following replacement algorithm, assuming one, two, three, four, six, or seven frames?

(a) LRU Replacement (b) FIFO Replacement (c) Optimal Replacement

Q. 6. (a) Explain the purpose of the open and close operation. 6

(b) What problem could occur if a system allowed a file system to be mounted simultaneously at more than one location? 6

Q. 7. Write short notes on any two :- 12 (a) PCB (b) Segmentation (c) Disk Structure

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Q. 1. (a) Distinguish between multiprogramming and multiprocessing. What are the key motivation for the development of each? 6

(b) Define, compare and contrast each of the following terms : Online, Real Time, Time Sharing and Interactive Compiling. 6

Q. 2. (a) What is spooling? How would an input spooling system designed to read punched cards from a card reader to operate. 6

(b) Describe the actions taken by a kernel to context switch between processes. 6

Q. 3. Consider the following set of process, with the length of the CPU burst time given in milliseconds: 12

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

The process are assumed to have arrived in the order P1,P2, P3, P4, P5 all at time 0. (a) Draw four Gantt charts that illustrate the execution of these processes using

FCFS, SJF, A non preemptive priority (A smaller number implies a higher priority) and RR (quantum) scheduling.

(b) What is the turnaround time of each process for each of the scheduling algorithm in part (a)?

(c)What is the waiting time of each process for each of the scheduling algorithm in part (a)?

Q. 4. (a) Write the difference between logical and physical address.

(b) Describe the following allocation algorithms. (i) First Fit (ii) Best Fit (iii) Worst Fit


Note: Attempt any five questions.

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Q. 5. (a) Why are segmentation and paging sometimes combined into one scheme? 6

(b) When virtual memory is implemented in a computing system it carries certain cost and certain benefits. List those costs and the benefits. Explain what measures you can take to ensure that this imbalance does not occur. 6

Q. 6. (a) What are the advantages and the disadvantages of recording the name of creating program with the file attribute? 6

(b) How do caches help improve performance? Why do systems not use more or large caches? 6

Q. 7. (a) State three advantages of placing functionality in a device controller, rather than in the Kernel. State three disadvantages. 6

(b) How does DMA increase system concurrency? How does it complicate the hardware design? 6

Q. 8. Write short notes on the following :- 12 (a) Demand Paging (b) Process control block

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Q. 1. (a) Define User, Job and process. Explain the relation between user, job process and address space.

(b) List benefit of spooling. Give one sentence explaining of each. Is spooling feasible for all types of I/O devices?

Q. 2. Define following terms (Any four) (a) Multiprogramming (b) Protection Hardware (c) Job Scheduler (d) Interrupt hardware (e) Process Scheduler (f) Virtual Memory (g) Primary Memory

Q. 3. What are functions of memory management in operating system? List techniques used for memory management.

Q. 4. Describe multiprogramming with the help of example. Give list of memory management technique used for programming.

Q. 5. Explain the role of operating system as resource manger.

Q. 6. Describe single contiguous allocation method. List advantages and disadvantages of this method.

Q. 7. Describe Demand page memory management technique along with advantages and disadvantages.

Q. 8. What are various page removal technique used for memory management? Explain any two techniques.

Q. 9. (a) Explain Job Scheduling and list function of job scheduler. (b) Explain process scheduling and list functions of process scheduler.

Q. 10. Describe the need of device management. Explain techniques used for managing and allocating devices.

Q. 11. What are Direct Access Storage Devices? Give example and explain one of them with diagram.

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Note: Attempt any seven questions. All Question carry equal marks.

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END TERM EXAMINATION THIRD SEMESTER [MCA] DECEMBER 2007

Time: 3Hours Maximum Marks: 60

Q.1 (a) Define operating system. (b) What is Race condition?

(c) Define physical file system. (d) What is job scheduling? (e) What is a device controller? (f) What is an interrupt vector?

Q.2 Describe various function of an operating system briefly. Q.3 Explain the following briefly: -

(a) Segmented Memory Management (b) Paged Memory Management (c) Relevance of Multiprogramming to Memory Management

Q.4 (a) Define Semaphores. How these are useful and used? Explain with examples. (b) What are the various criteria to be taken for selecting a scheduling policy? Explain briefly with example. Q.5 Differentiate between the following: -

(a) Multiplexing and Buffering (b) Channels and Controls Units (c) Dedicated and Shared devices

Q.6 (a) Differentiate between logical and physical file system with their relative merits and demerits. (b) Describe the concept of fragmentation briefly. Q.7 Write short notes on the following: -

(a) Virtual devices (b) Direct Memory Access (DMA)

(c) Symbolic file system

Paper Code: MCA201 Subject: Operating System

Note: Attempt Five questions in all including Q.no. 1. Which is compulsory. All question carry equal marks.

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END TERM EXAMINATION

THIRD SEMESTER [MCA] DECEMBER-2008 Paper Code: MCA 201 Subject: Operating System Paper Id-44201 (Batch: 2004-2007) Note: Attempt any five questions. (26=12) Q1. (a) Define Multi programmed Batches Systems.

(b) Explain Real Time System.

(c) Define Multi-user Multi Tasking System.

(d) What is Multi Processor Scheduling?

(e) Discuss Time System.

(f) Define Storage Device. Q2. What is an operating System? Define the Protected Mode and Supervisor Mode. (12) Q3. Explain the following briefly: (43=12) (a) What is Scheduling Policy? Describe the Basic Concepts, Criteria and

Algorithm Evaluation in brief. (6)

(b) What is Synchronization? Define the classical Problem of Synchronization (6)

Q5. Explain the following briefly:- (34=12) (a) Swap Space Management (b) Stable-Storage Implementation (c) Device Allocation Consideration Q6. Differentiate between the following:- (34=12)

(a) Basic file system and Logical File System (b) File systm Interface and File File System Implementation (c) Directory Implementation and Directory Structure

Q7 Write short notes on the following:- (43=12) (a) Access Control Verification (b) Disk reliability (c) Parallel System. (d) Shared Devices

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1

END TERM EXAMINATION THIRD SEMESTER [MCA] December2009

Time:3 hours Maximum marks:60

Q1 Answer all the following question briefly: (2X10=20)

(a) What are the advantages of having different time quantum sizes on different level of a multilevel queuing system?

(b) Write an algorithm to solve problem of critical section among two processes. (c) Differentiate between constant linear velocity and constant angular velocity of disk

structure. (d) Explain file allocation method implanted in unix. (e) (f) Consider a logical adderess space of eight pages of 1024 words each,mapped onto

a physical memory of 32frames.how many bits are there in the logical address? How many bits are there in the physical address?

(g) Describe a mechanism by which one segment could belong to the address space of two different processes?

(h) What is Beladys Anomaly?explain. (i) degree of multiprogramming control the performance of the computing system

comment. (j) How thread creation differ from that of process creation? Briefly explain.

UNITI

Q2 consider the following page reference string: 4,6,8,0,4,9,3,2,4,6,2,9,3,0,3,6,4,7. Assume there are four frames. How many page faults will occur for the following replacement algorithms(show computation)?which one is best algorithm? (10)

(a) LRU replacement (b) FIFO replacement (c) LFU replacement (d) Optimal page replacement

Q3 (a) why are segmentation and paging sometime combined into one scheme? What are their Advantages and disadvantages? (5) (b) given the memory partition of 400K,100K,500K,800K (in order) how would each of the Firstfit, bestfit and worstfit algorithms place processes of 190K,420,171K,540K(in

Order)?which algorithm makes the efficient use of memory? (5)

Paper code:MCA201 subject:operating system Paper id44201 (batch:20042008)

Note: Q1 is compulsory. Attempt one question from each unit.

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UNITII

Q4 (a) explain dining philosophers problem with its algorithm. (6)

(b) when virtual memory is implemented in a computing system,it carries certain cost and certain benefits. List thosecosts and the benefits. It is possible for the costs exceed the benefits. Explain what measures you can take to ensure that this imbalance does not occur.(4)

Q5 consider the processes listed in the following table,usin g priority scheduling for:(a)preemptive and (b) non preemptive

Answer the following: (i) Draw gantt charts illustrating the exception og these processes. (10) (ii) What is the turnaround time of each process? (iii) What is the average throughout of each of these?

Note that the small interger value(of priority no) indicate high order of priority. UNITIII

Q6 consider the following snapshots of a system:

Answer the following questions using the bankess algorithms: (a) What is the content of the matrix need? (10) (b) Is the system in a safe state? (c) If a request from process P1 arrives for (0 4 2 0) can request be granted immediately.

Q7 (a) suppose that a disk has 5000 cylinder numbered 0 to 4999. The drive is currently at 143 and previous record was at 150. The queue of pending request, in FIFO is 28, 1470,913, 2050, 1509, 1022,20,389,4888,260. Starting from current head position, what is total distance that disk moves to satisfy all pending request for each if the following algorithms: (i) SSTF (ii) SCAN (iii) LOOK (6)

(b) explain secondary storage structure having constant access time T(i,j). (4)

process Arrival time Burst time Priority no. A 0 2 2 B 0 7 4 C 1 3 1 D 3 1 5

Allocation ABCD

Max ABCD

Available ABCD

P0 P1 P2 P3 P4

0012 1000 1354 0632 0014

0012 1750 2356 0652 0656

1520

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3

UNITIV

Q8 (a) explain the sequential and direct file access method. How can a sequential file be simulated on a direct access file? Explain. (5)

(b) what is logical file system? How it is different from that of physical file system? Explain with examples. (5)

Q9 write short notes on any two of the following: (5X2=10)

(a) Clustered vs. Distributed system (b) Deadlock prevention vs.deadlock avoidance (c) Process control block

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(Please write your Exam Roll No.) Exam Roll No. ..........................................

END TERM EXAMINATION THIRD SEMESTER [MCA] DECEMBER 2010


Paper ID:44201


Note: Attempt five questions. Select one question from each unit including Q.1 which

is compulsory

Q1 Answer all the following question briefly: - (2x 10=20)

(a) What is the convoy effect? Briefly explain.

(b) What is the main difficulty that a programmer must overcome in writing an operating

system for a real-time environment?

(c) What data structures can be used for directory information?

(d) Higher degree of multiprogramming badly affects the performance of the computing

system- comment.

(e) What is FAT? How is FAT beneficial?

(f) Differentiate between Constant Linear Velocity and Constant Angular Velocity of disk

structure.

(g) Consider a file system where a file can be deleted and its disk space reclaimed while

links to that file still exist. What problems may occur if a new file is created in the

same storage area or with the same absolute path name? How can these problems

be avoided?

(h) Differentiate between Logical and Physical file system.

(i) Suppose a process P wants to wait for two messages, one from mailbox A and one

from Mailbox B. What sequence of send and receive should it execute?

(j) What is SPOOLING? Briefly explain.

UNIT-I

Q2 (a) Describe a mechanism by which one segment could belong to the address space of

two different processes. (5)

(b) How many page fault occur for Optimal and LRU algorithms for the following

reference string, for four page frames and which algorithm is the best(show

computations)? (5)

1,2,3,4,5,3,1,6,7,8,7,8,9,7,8,9,5,4,5,4,2

Q3 (a) Given the memory partition of 600K , 200K, 250K,500K (in order) how would each of

the first-fit, best-fit and worst-fit algorithms place processes of 128k, 581k, 411k,

221k (in order)? Which algorithm makes the efficient use of memory? (5)

(b) What are the different ways to implement Least Recent Used algorithm, to determine

which page is decided as a victim page? (5)

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UNIT-II

Q4 Consider the processes listed in the following table:-

Processes Arrival Time Burst Time Priority No.

P1 1 20 2

P2 4 16 1

P3 5 04 3

Answer the following:- (a) Draw 3 Gantt charts for Priority (pre-emptive), SJF (non pre-emptive) and RR (with

the quantum 4). (b) Calculate avg. waiting time for each of the above scheduling. (c) Calculate avg. Turnaround time for each of the above scheduling. Note that the small

integer value (of priority No.) indicates high order of priority. Q5

(a) Explain Readers-writers problem with its algorithm. (6) (b) How are synchronization tools helpful? Explain critical region and monitors. (4)

UNIT-III

Q6 (a) What are the safety algorithm and Resource Request algorithm? Explain them with

example. (5)

(b) Explain secondary storage structure having small variance in access time T(i, j). (5)

Q7 (a) Suppose that a disk drive has 2000 cylinders numbered 0 to 1999. The drive is

currently at 10 and previous record was at 140. The queue of pending requests, in FIFO is 68, 1460, 811, 200, 1500, 1022, 28, 1389, 887, 160. Starting from current head position, what is the total distance that disk moves to satisfy all pending request for each algorithms:- (i) SSTF (ii) C-SCAN (iii) LOOK (6)

(b) What are the differences between techniques of Buffering from that of Blocking? Explain with example. (4)

UNIT-IV

Q8 (a) How do caches help to improve performance of the systems? Why do no systems

use more or larger caches, if they are so useful? Explain with example. (5) (b) Explain Indexed and Contiguous file allocation methods with suitable example. (5)

Q9 Write short notes on any two of the following:- (5x2=10)

(a) Real-Time vs. Embedded Systems (b) Multi-Level Feedback Queues (c) Deadlock Prevention vs. Deadlock Avoidance

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Paper code: MCA-106 Subject: Operating systems

Note: Question 1 is compulsory. Attempt four questions from rest.

Q1. Explain in brief: (2X10=20)

(a) Define Thrashing.

(b) List the differences between Internal Fragmentation and external Fragmentation.

(c) What do you know about Spooling.

(d) Why does the page size is of 2n.

(e) List the necessary and sufficient conditions of deadlock.

(f) Explain the disadvantages of second attempt of Dekkers algorithm for process

synchronization.

(g) List the differences between preemption and non-preemption.

(h) What is buffering.

(i) List the disadvantages of Index allocation strategy.

(j) Define Multiprogramming.

Q2. Discuss about safe state and usefulness of safety algorithm for Deadlock avoidance (10)

Q3. Describe the state transition model in which few states resides in secondary memory.

Also describe the use of these states. (10)

Q4. Consider the following process: (10)

Process Arrival Time Burst Time P1 P2 P3

0.0 msec 0.5 msec 1.0 msec

6 ms 4 ms 10 ms

Find the weighted turnaround time for shortest job first technique and future knowledge

technique.

Q5. (a) List the disadvantages of paged memory management techniques and segmentation

memory management techniques. (5)

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(b) A variable partition memory system has given partition size 30K, 50K, 10K, 5K, and

20K. A new process of 15K is to be loaded. Which partition would be appropriate using first

fit, best fit and worst fit techniques. Explain your answer in detail. (5)

Q6. (a) Is disk scheduling other than FCFS scheduling useful in a single user environment?

Explain your answer. (4)

(b) Suppose that a disk drive has 5000 cylinders, numbered 0 to 4999. Initially head is at cylinder 143 and the previous request was at cylinder 125. Consider the following head requests:

86, 1470,913 ,1774 ,948 ,1509 ,1022 ,1750 ,130.

Determine the total distance for the following disk scheduling algorithms:

(i) C-SCAN (ii) LOOK (6)

Q7. List the differences between Linux Operating System and Windows XP operating

system in view of operating systems resources. (10)

Q8. Write short notes on any two: (2X5=10)

(a) Cryptography

(b) Block Multiplexing

(c) Beladys Anomaly

(d) System Calls

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(Please write you Exam Roll No.) Exam Roll No. ..

END TERM EXAMINATION SECOND SEMESTER [MCA] MAY-JUNE 2012


Time : 3Hours Maximum Marks :60

Note : Attempt any five questions including Q.no.1 which is compulsory

Q1 Answer the following:-

(a) Compare distributed systems and real-time systems. Give their applications. (2)

(b) Explain how monitors are used in synchronization. (2)

(c) Mention the necessary conditions for a deadlock to occur. (2)

(d) Explain features of device management. (2)

(e) Mention the components in storage area network. Give its working. (2)

(f) Explain various types of program threats. (2)

(g) Explain the working mechanism of symmetric key and asymmetric key encryption

techniques used in cryptography. (3)

UNIT-I

Q2 (a) Explain the features of operating system components. (5)

(b) explain Process Control Block. Draw the block diagram of process transition

states. (5)

(c) What resources are used when a thread is created? How do they differ from those

used when a process is created? Describe the actions taken by a thread library to

context-switch between user-level threads. (1+1+3)

OR

Q3 (a) Explain the term operating system. Differentiate between Hard operating system and

soft ooperating system. (5)

(b) Write short note on multiple processor scheduling with the examples. (5)

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(c) Discuss and explain the scheduling criteria and its algorithms in brief. (5)

UNIT-II

Q4 (a) Compare segmentation and paging schemes used in memory management. Give

their applications. (6)

(b) Consider the following workoad:

Process Burst Time Priority Arrival Time

P1 50ms 4 0ms

P2 20 ms 1 20ms

P3 100ms 3 40ms

P4 40ms 2 60ms

(i) Draw the Gantt chart to illustrate the cpu scheduling for shortest remaining

time, non-preemptive priority (a smaller priority number implies higher priority)

and round robin with quantum 30ms. (6)

(ii) Calculate the turnaround time for each process in the above mentioned CPU

scheduling algorithms. (3)

OR

Q5 (a) Define Semaphores. Write the functions for wait() and signal() used in semaphores.

Give the applications for binary semaphores and counting semaphores.

(1+2+2)

(b) Consider a system consisting of m resources of the same type which are being

shared by n processes. A process can request or release only one resource at a time.

Show that the system is deadlock free if the following two conditions hold: (4)

(i) The maximum need of each process is between one resource and m resources.

(ii) The sum of all maximum needs is less than m+n.

(c) Consider the following page reference strings:- (6)

1, 2, 3, 4, 2, 1, 5, 2, 3, 7, 6, 3, 5, 1, 2, 3, 6

How many page faults would occur for the following replacement algorithms, assuming

four frames? Assuming all frames are initially empty and first unique pages will cost one

fault each.

(i) LRU replacement (ii) FIFO replacement (iii) Optimal replacement

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UNIT-III

Q6 (a) Compare the features of dedicated devices, shared devices and virtual device. Give

their respective applications. (6)

(b) Explain buffering and multiplexing in device management. (6)

(c) Explain device allocation strategies in multi-user systems. (3)

OR

Q7 (a) compare performance issues in disk scheduling algorithms. (6)

(b) Explain how bad blocks are managed in disk structures? (3)

(c) Disk requests are made for disk driver to cylinders 10, 22, 20, 2, 40, 6 and 38. A seek

takes 6 msec per cylinder. The initial position of disk arm is at cylinder 20. How much

seek time is needed for the following:- (6)

(i) FCFS (ii) SSTF (iii) C-SCAN

UNIT-IV

Q8 (a) Explain network related threats and give their respective solutions. (4)

(b) Draw and explain the architecture of Linux Operating System. (4)

(c) Mention the features of various file allocation methods. (4)

(d) Explain virtual file system. (3)

OR

Q9 Write short notes on any three of the following:- (5X3=15)

(a) Authentication and Intrusion detection

(b) Directory Implementation

(c) Windows XP

(d) Security and Cryptography

**********

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(Please write your Exam Roll No.) Exam Roll No. .

END TERM EXAMINATION

SECOND SEMESTER [MCA] MAY JUNE 2013

Paper Code: MCA-106(New) Subject: Operating Systems

Time : 3 Hours Maximum Marks:60

Note: Attempt any five questions. Select one question from each unit. Q. 1 is compulsory.

Q1. Answer all the following questions briefly: (10X2)

(a) What about virtual device ?

(b) Explain evolution of Computer ?

(c) Define CISC & RISC processor ?

(d) What is a time sharing parallel ?

(e) Describe the Process scheduling ?

(f) What is a real-time systems ?

(g) What is Cooperating Processes ?

(h) What is the function of storage device ?

(i) List the different layers of Networking ?

(j) Explain Algorithms Evaluation ?

UNIT-I

Q2. (5X2=10)

(a) What is an operating system structure ? Explain the different Components of

operating system with merits and demerits.

(b) What is a Critical Section problem ? How it effects the System. System the

solution for improvement.

Q3. Write short notes on the following:

(a) Page replacement (3)

(b) Segmentation (3)

(c) Thrashing (4)

P.T.O

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UNIT-II

Q4. (10)

(a) Define the Device Management. Explain various Techniques for

device management.

(b) What is Swap-Space Management? How it effects Device System ?


(a) Disk Reliabilty

(b) Buffering

(c) Block Multiplexing

UNIT-III

Q6. (10)

(a) Explain the Linux Operating System. Differentiate with Windows

Operating System.

(b) What is the Cryptography? Discuss its functionality in details.

Q7. Explain in short:

(a) System threats

(b) Goals of protection

(c) Directory Implementation

UNIT-VI

Q8. (10)

(a) Write about the file system structures. What is a basic file system?

(b) Describe the security problem for the system ? How to protect our

system from the security risk?


(a) Multi programming

(b) Semaphores

(c) Message passing

(d) Demand paging

(e) Multiple Paths

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