2076
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.
Defined interactive system goals? List various interactive scheduling algorithms. Consider following process data and compute average waiting time and average turnaround time for RR(quantum 10) and priority scheduling algorithms.
| PID | Burst Time | Arrival Time | Priority |
|---|---|---|---|
| A | 16 | 0 | 1 |
| B | 37 | 12 | 2 |
| C | 25 | 7 | 3 |
How Second Chance page replacement algorithm differs from FIFO page replacement policy? Discuss the concept of Belady’s anomaly with suitable example.
What is the main objective of disk scheduling algorithms? why SSTF is not practically feasible? Assume that we have disk with 100 tracks and currently head is at track number 35. What will be the seek time for the algorithms SCAN and LOOK for processing IO requests queue: 52, 67, 27, 11, 43, 85, 18, 75, 92, 8?
Attempt any EIGHT question.
What are two modes of OS? Discuss different OS structures briefly.
When threads are better than processes? Explain the concept of user level threads in detail.
Differentiate between multi programming and Monoprogramming. What will be the CPU utilization with 6 processes with 60% IO waiting time are in memory?
How can you manage free disk space? Explain the linked list approach of managing free disk space with example.
When programmed IO is suitable than other IO handling techniques? Explain the process of IO handling using DMA.
Differentiate between deadlock and starvation? Discuss the process of detecting deadlocks when there are multiple resources of each type.
What is problem associated with semaphores? Explain the concept of monitors in brief.
Why program relocation and protection is important? Explain the technique of achieving program relocation and protection.
Write short notes on:
a. Linux File System
b. Resource Allocation Graph
*** END OF QUESTION PAPER ***
Interactive System Goals Interactive systems focus on fast response to users. Major goals are: - Fast Response Time: System should respond quickly to user actions. - Fairness: Each user/process gets a
Second Chance Page Replacement vs FIFO FIFO (First-In-First-Out) Page Replacement: - The page that has been in memory for the longest time is removed first. - It does not consider whether the page was
(a) Main objective of disk scheduling algorithms The main objective is to minimize disk head movement (seek time) so as to: - Reduce average seek time and latency, - Improve throughput (I/O requests s
Two Modes of Operating System Modern operating systems work in two modes to ensure security and proper control over system resources: 1. User Mode - Application programs run in this mode (e.g., bro
When Threads Are Better Than Processes Threads are preferred over processes in situations where tasks need to run simultaneously within the same application. They are better when: - Faster Context Swi
And more questions available on this page.