this is for testing


VIth Semester BSc Computer Science Model Examination, March 2018

Operating Systems

Time: 3 Hours                                                          Maximum : 80 Marks


  1. Answer all questions.(10 x 1 = 10 Marks)
  2. What do you mean by a process ?
  3. What is PCB ?
  4. What is hit ratio?
  5. Name any two popular android operating systems.
  6. In _____ memory management technique. the logical address space is viewed as a collection of logically related entities such as library routines. data structures, symbol tables, main programs etc
  7. The processes that are residing in main memory and are waiting to execute are kept on a list called?
  8. The number of processes residing in memory in a unit amount of time is known as —-.
  9. In UNIX, a new process is created by system call.
  10. The process waiting to be assigned to a processor is in state____
  11. Module that gives control of the CPU to the process selected by the short-term scheduler.______ is used as a bridge between database anddataset.


  1. Answer all questions. (5 x 2 = 10 Marks)


  1. Write the code to implement mutual exclusion condition in critical section problem using a test and set instruction.
  2. Differentiate between binary semaphore and counting semaphore.
  3. How memory protection and allocation are implemented in contiguous memory allocation.
  4. Define a deadlock.
  5. Distinguish between logical and physical address.


  1. Answer any four questions from eight. (4 x 5 = 20 Marks)


  1. Differentiate between long term scheduler and short term scheduler .
  2. Explain real time systems and distributed systems .
  3. Explain the process of starvation and how it can be prevented.
  4. What are the conditions to be satisfied to solve the critical section problem ?
  5. What is the difference between deadlock prevention and deadlock avoidance ?
  6. Distinguish between internal and external fragmentation ?
  7. How memory protection and allocation are implemented in contiguous memory allocation.
  8. With the help of an example, explain the process of address translation from logical address to physical address in paging.


  1. Answer any two questions. (5 x 8 = 40 Marks)


  1. Explain the classic problems of Synchronization.
  2. What is meant by page replacement ? Explain any two page replacement algorithms with examples.
  3. Explain in detail, the demand paging system with emphasis to handle page faults.
  4. Explain about various types of operating systems. Briefly mention the features of these operating systems. Discuss any four CPU scheduling algorithms.
  5. Explain about various deadlock handling techniques. Explain the resource-allocation graph algorithm for deadlock detection with relevant diagram
  6. By illustrating the structure of process, say P1, explain the Petersons solution to critical section problem.
  7. Explain sequential and indexed file access methods.
  8. What is thrashing? What is the cause of thrashing? Explain the working set model.




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