Bachelors Level/Second Year/Third Semester/Science bit/third semester/operating systems/syllabus wise questions

Bachelors In Information Technology

Institute of Science and Technology, TU

Operating Systems (BIT204)

Year Asked: 2078, syllabus wise question

Input / Output Management
1.
Suppose that a disk has 100 cylinders, numbered 0 to 99. The drive is currently serving a request at cylinder 45. The queue of pending request, in FIFO order is: 88, 72, 13, 74, 48, 9, 22, 50, 35 and 30. What is the total distance (in cylinders) that the disk arm moves to satisfy all pending request for each of the following disk scheduling algorithms? a) FCFS b) SCAN c) SSTF [10]
2.
What is DMA? Explain how it works in brief with suitable diagram. [5]
Introduction and Evolution
1.
What is an operating system? Differentiate between time sharing and real time operating system. [5]
Memory Management and File Systems
1.
Why virtual memory technique is used in the computer system? What is logical address? Explain the process of conversion of logical address to physical address in single level paging scheme. [10]
2.
What are different types of file? Describe the sequential and random access of files. [5]
3.
A 2 GB hard disk has 2 KB block size, calculate the size of bitmap for bitmap based free space management. [5]
Process Management and Synchronization
1.
What is critical section? What are the operations that can be performed on the semaphore? Explain the solution to producer consumer problem using semaphore. [10]
2.
Draw and describe the 5-state process model. [5]
3.
what is deadlock? What ate necessary conditions for deadlock? Explain. [5]
4.
What is thread? Explain user level thread and kernel level thread. [5]
5.
Consider the following set of processes, with the length of CPU brust time given in milli seconds. The processed are assumed to have arrived in the order A, B, C and D all at time 0. What is the turnaround time and waiting time for the scheduling algorithms, RR (quantum = 3) and Priority Algorithm.

$\begin{array}{|c|c|c|}\hline \text{Process} & \text{CPU Burst} & \text{Priority} \\ \hline A & 8 & 3 \\ B & 9 & 1\,(\text{Lowest}) \\ C & 10 & 2 \\ D & 6 & 4\,(\text{Highest}) \\ \hline \end{array}$
[5]
System Structures
1.
What is kernel? Differentiate between monolithic and microkernel structure. [5]