2071
Bsc CSIT / Semester 4 / Science
Computer Science and Information Technology
Operating System
Full Marks: 60 + 20 + 20
Pass Marks: 24 + 8 + 8
Time: 3 Hours
Candidates are required to give their answers in their own words as far as practicable.
The figures in the margin indicate full marks.
Attempt any TWO question.
How thread based execution minimizes the context switching problem of process based execution? Explain the different multithreading model.
What is page fault? Consider the following page reference string; 3, 3, 5, 4, 7, 1, 5, 5, 1, 4, 3, 7, 6, 3, 4, 1. How many
page faults would occur for each of the following page replacement algorithms assuming 4 page frames?
a) LRU page replacement
b) FIFO page replacement
c) Optimal page replacement
d) Clock replacement
Suppose the head of a moving- head disk with 200 tracks, numbered 0 to 199 is currently serving request at tracks 143 and has finished a request at track 125. The queue it requests is kept in the FIFO order
86, 147, 91, 177, 94, 150, 102, 175, 130Attempt any EIGHT question.
How operating is as a resource manager? Explain.
For each of the following transitions between the processes states, indicate whether the transition is possible. If it
is possible, give an example of one thing that would cause it.
a) Running -> Ready
b) Running -> Blocked
c) Blocked -> Running
Define file and directories. Explain about protection mechanism.
Differentiate between internal and external fragmentation with example.
What are the segmentation and paging? Why they are combined into one scheme?
What is DMA? Explain how it works.
What do you understand by deadlock detection and recovery? Discuss.
Explain how file allocation table (FAT) manage the files. Mention the merits and demerits of using FAT.
Write short notes: (Any two)
a) Best Fit vs. Worst Fit
b) Swapping
c) Semaphores
*** END OF QUESTION PAPER ***
Thread-Based Execution and Multithreading Models 1. How Thread-Based Execution Minimizes Context Switching - Definition of Thread: A thread is the smallest unit of CPU execution within a process. Mul
Page Faults and Page Replacement Algorithms 1. Definition of Page Fault A page fault occurs when a process tries to access a page that is not currently in main memory. - The operating system then l
Disk Scheduling Algorithms and Total Head Movement Given: - Disk tracks: 0 – 199 - Current head: 143 - Previous head: 125 → direction = toward higher tracks - Request queue (FIFO): 86, 147, 91,
Operating System as a Resource Manager 1. Definition An Operating System (OS) acts as a resource manager by efficiently allocating and controlling all hardware and software resources of a computer sy
Process State Transitions | Transition | Possible? | Example / Explanation | |--------------------|-----------|---------------------| | Running → Ready | Yes | Preemption by scheduler:
And more questions available on this page.