Download PTU B.Sc CS-IT 2020 March 4th Sem 72321 Operating Systems Question Paper

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Roll No. HEEEEEEEEEE Total No. of Pages : 02
Total No. of Questions : 07

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B.Sc.(CS) (2013 & Onwards) (Sem.-4)
OPERATING SYSTEMS
Subject Code : BCS-405
M.Code : 72321
Time : 3 Hrs. Max. Marks : 60

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INSTRUCTION TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks each.
2. SECTION-B contains SIX questions carrying TEN marks each and a student has to attempt any FOUR questions.

SECTION-A

1. Answer briefly :
   1. What is the difference between Multiprogramming and Multiprocessing?

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   2. What is the role of context switching in CPU scheduling?
   3. Define Throughput and Turnaround Time.
   4. List any two dissimilarities between Process and Thread.
   5. Define Non Pre-emptive Scheduling.
   6. Explain Mutual Exclusion.

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   7. How Sequential files are different from Random access files?
   8. Write short note on Virtual Memory.
   9. What is the limitation of Access Control Lists?
   10. Differentiate between viruses and worms.

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SECTION-B

2. 1. How operating system is used as a resource Manager?
   2. Discuss different states of a Process.
3. Following is the information related to some processes :
   

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   Process	Burst	Priority	Arrival Time
   P1	10	3	0
   P2	8	2	2
   P3	4	1	8
   P4	8	2	16
   P5	12	1	24
   P6	4	3	30

   
   Using the above information, Compute the average waiting time and average turnaround time for the following algorithm :
   1. Shortest Job First
   2. Pre-emptive Shortest Job First
   3. Priority scheduling
   4. Pre-emptive Priority Scheduling

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   5. Round Robin (Time Quantum of 3 units)
   Ignore the arrival time for Non pre-emptive algorithm.
4. 1. What is meant by Process Synchronization? Explain the role of Critical Section and Semaphores for Synchronization.
   2. What is the role of Socket in Inter Process Communication?

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5. 1. Compare LFU and Optimal Page replacement algorithm with the help of an example.
   2. What are the attributes of a file? Explain structure of file system in detail.
6. Define Page Fault. What are the reasons for occurrence of page faults? Write the steps required for servicing page faults.
7. 1. Explain the role of I/O traffic controller, I/O device handler and I/O scheduler in device management.

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   2. What is denial of services? How we can handle such attacks?

NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any page of Answer Sheet will lead to UMC against the Student.

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