2080
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 DMA operation is performed? Consider a disk with 200 tracks and the queue has random requests from different processes in the order : and . Find the seek time using and . Assume the initial position of head as 100.
How do you distinguish between deadlock and starvation ? Describe and Explain working mechanism of TLB.
Why do we need to schedule process? Find the average waiting time and average turnaround time for the following set of processes using and shortest remaining time next.
| Process | CPU brust time | Arrival time |
|---|---|---|
| P1 | 20 | 0 |
| P2 | 25 | 15 |
| P3 | 10 | 30 |
| P4 | 15 | 45 |
Attempt any EIGHT question.
What is system call ? Describe the transition between different states of process.
Discuss about contiguous and linked list file allocation technique.
Why do we need virtual memory? Describe the sructure of a page table.
Illustrate the term safe and unsafe state in deadlock prevention with scenario.
How lock variable is used in achieving mutual exclusion? Describe.
Why do we need hierarchical directory system? Explain structure of disk.
Find the number of page fault using FIFO and LRU for the reference string with frame size 3.
Define working set. How does clock replacement algorithm works?
Write short notes on :
a. Inode
b. RAID
*** END OF QUESTION PAPER ***
1. Direct Memory Access (DMA) Definition: - DMA is a method that allows I/O devices to transfer data directly to/from memory without CPU intervention. - CPU is only involved at the start and end o
1. Difference Between Deadlock and Starvation | Feature | Deadlock | Starvation | |---------|----------|------------| | Definition | A state in which two or more processes are waiting indefinitely for
1. Why Process Scheduling is Needed - The CPU is a shared resource among multiple processes. - Scheduling ensures: 1. Efficient CPU utilization 2. Fairness among processes 3. Reduced wai
1. System Call Definition: A system call is a request made by a user-level program to the operating system (kernel) to perform operations that cannot be done directly by the program, such as: - File
File Allocation Techniques Files can be stored on disk using different allocation methods: --- 1. Contiguous Allocation - File occupies continuous disk blocks. - Example: File F1 uses blocks 10, 11
And more questions available on this page.