Operating System 2018- MCA 2nd year AKTU
Printed Pages:02 Sub Code:RCA301
Paper Id: 214301 Roll No. _____________________
MCA
(SEM-III) THEORY EXAMINATION 2018-19
OPERATING SYSTEMS
Time: 3 Hours Total Marks: 70
Note: 1. Attempt all Sections. If require any missing data; then choose suitably.
SECTION A
1. Attempt all questions in brief. 2 x 7 = 14
- What are batch systems?
- What do you mean by system calls?
- What is the use of job queues?
- What is independent process?
- What is dispatcher?
- Define throughput?
- Differentiate between process and thread.
SECTION B
2. Attempt any three of the folloing: 7 x 3 = 21
- Discuss various operating system services with example.
- What is information in the PCB? Discuss it with diagram.
- Find the average waiting time (A.W.T.) and average turnaround time (A.T.A.T.) for executing the following process using.
- Preemtive shortest-job first
- Non-preemptive shortest-job first?
Process Arrival Time Burst Time P1 0 5 P2 1 13 P3 2 8 P4 3 4 P5 4 10 - Name four page replacement algorithms. Describe any one with example.
- Define critical section problem. Explain Peterson’s solution to solve critical section problem.
SECTION C
3. Attempt any one part of the folloing: 7 x 1 = 7
- Discuss DMA transfer and DMA controller.
- What do you mean by cache memory? Discuss various mapping technique of cache memory.
4. Attempt any one part of the folloing: 7 x 1 = 7
- What is deadlock? How can we avoiding deadlocks occur? Explain it.
- Suppose we have five processes and three resources, A, B, and C. A has 10 instances, B has 5 instances and C has 7 instances. Can the system execute the following processes without deadlock occurring, if yes find safe sequence?
Process | Allocation | Maximum need | ||||
---|---|---|---|---|---|---|
A | B | C | A | B | C | |
P1 | 0 | 1 | 0 | 7 | 5 | 3 |
P2 | 2 | 0 | 0 | 3 | 2 | 2 |
P3 | 3 | 0 | 2 | 9 | 0 | 2 |
P4 | 2 | 1 | 1 | 2 | 2 | 2 |
P5 | 0 | 0 | 2 | 4 | 3 | 3 |
5. Attempt any one part of the folloing: 7 x 1 = 7
- Discuss the following storage placement strategies with suitable examples:
- Best fit
- First fit
- Worst fit
- Differentiate between:
- Hard and soft real time system.
- Paging and segmentation.
6. Attempt any one part of the folloing: 7 x 1 = 7
- What is process synchronization? Give the solution to reader writer proble, using semaphores.
- Consider the following page reference string:1, 2, 3, 4, 5, 6, 3, 1, 2, 3, 4, 6, 4, 5, 2, 6. Calculate number of page faults using LRU and OPTIMAL Page replacement algorithm. Assume number of frames as three.
7. Attempt any one part of the folloing: 7 x 1 = 7
- Which allocation scheme will minimize the amount of space required in directory structure and why?
- Explain short seek time first (SSTF) disk scheduling. Why SSTF scheduling tends to favor middle cylinders over the inner most and outer most cylinders?