IF 253 — OPERATING SYSTEMS

[aruljothi]

IF 253 — OPERATING SYSTEMS
Time : Three hours   Maximum : 100 marks
Answer ALL questions.
PART A — (10  2 = 20 marks)
1.   What is meant by thrashing?
2.   Explain the difference between logical address and physical address space.
3.   What is the purpose of system calls?
4.   Explain the difference between symmetric and asymmetric multiprocessing.
5.   The ratio between the main memory cycle time and cache memory time is 8 : 1.  Calculate the effective memory cycle time for a system who cache miss ratio    is 6%.
6.   What is a Time sharing system?
7.   What is a Context switch?
8.   What is dynamic loading and dynamic linking?
9.   Define the essential properties of real time Operating System.
10.   What are the advantages of having an inverted page table?
PART B — (5  16 = 80 marks)
11.   (i)   Discuss the critical section problem with one example.   (
   (ii)   Briefly explain the Threads support in Solaris 2 Operating system.   (
12.   (a)   Consider the following snapshot of a system.  Execute Banker's algorithm answer the following :
   Allocation   Max   Available

001   001   152

100   175   

135   235   

063   065   

001   065   
      (i)   Is the system in a safe state?  If the system is safe, show how all the process could complete them execution successfully.  Explain.   (10)
      (ii)   If a request from process   arrives (0, 4, 2) can the request be granted?         (6)
Or
   (b)   Consider the following page reference string.
            1,  2,  3,  4,  2,  1,  5,  6,  2,  1,  2,  3,  7,  6,  3,  2,  1,  2,  3,  6.
      Calculate the number of page faults would occur for the following page replacement algorithm with frame size of 3 and 4.  Initially all the frames are empty.
      (i)   LRU
      (ii)   FIFO
      (iii)   Optimal.         (16)
13.   (a)   Assume the following workload in a system.  All jobs arrive at time 0 in the order given.  Lower number is the highest priority.
Job   Burst time   Priority
A   10   3
B   6   1
C   7   4
D   4   2
      (i)   Give a Gantt chart illustrating the execution of three job using FCFS, Round Robin (quantum = 3) and SJF.   (6)
      (ii)   Calculate the average waiting time for each of the above scheduling algorithm.         (10)
Or
   (b)   (i)   List five services provided by an Operating System.  Explain how each provides to the users.      (
      (ii)   Explain the linked file allocation method.  What are its advantages and disadvantages?         (
14.   (a)   (i)   What is DMA transfer? Explain all the steps involved in a DMA transfer.         (
      (ii)   Briefly explain the different assembly language statements.   (
Or
   (b)   Briefly explain the Disk Management and Swap Space Management.   (16)
15.   (a)   Discuss briefly the various issues involved in implementing Inter Process Communication (IPC) in message passing system.   (16)
Or
   (b)   (i)   Explain the difference between External Fragmentation and Internal Fragmentation. How to solve the fragmentation problem using Paging?         (7)
      (ii)   Compare short term, medium term and long term scheduling.   (9)
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[sams.raghu]

B.Tech I Semester Supplimentary Examinations, February 2008

2008 Jawaharlal Nehru Technological University

OPERATING SYSTEMS

( Common to Computer Science & Engineering, Electronics & Instrumentation Engineering, Information Technology, Electronics &
Control Engineering, Computer Science & Systems Engineering and Electronics & Computer Engineering)

Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks

1. Some CPUs provide for more than two modes of operation. What are two possible
uses of these multiple modes? Explain. [16]

2. What is Process Control Block? Explain its structure. [16]

3. Define monitor. What are its characteristics? [16]

4. What are the different LINUX spinlcocks? Explain. [16]

5. Explain about address binding for a user program and discuss multi step processing
of a user program. [16]

6. What is the difference between preemptive and non preemptive scheduling? Explain
an algorithm for each scheduling type. [16]

7. (a) List and explain three blocking methods.

(b) What is the relationship between a pathname and a working directory?
(c) What criteria are important in choosing a file organization? [6+5+5]

8. (a) Discuss the three options available in Windows 2000 for requesting access.
(b) Describe the generic access of Windows 2000.
(c) How is the AES expected to be an improvement over triple DES? [6+5+5]