III/BCA/303 Student's Copy
Professional Course Examination, November 2018
3rd Semester
BACHELOR OF COMPUTER APPLICATIONS
Course BCA-303
Operating Systems
Revised
Full Marks 75
Time 3 hours
PART A—OBJECTIVE
Marks 25
The figures in the margin indicate full marks for the questions
SECTION—A
Marks 15
Tick the correct answer in the brackets provided 1×10=10
1. Operating system does not interact with the computer directly. Each user
prepares his job on an off-line device like punch cards and submits it to
the computer operator. This is known as
batch operating system
time-sharing operating system
distributed operating system
network operating system
/368 1 Contd.
2. Which of the following is not an operating system service?
Communication
Error detection
Program execution
System call
3. The time it takes for the dispatcher to stop one process and start another
running is known as
scheduler
CPU utilization
context switch
dispatch latency
4. Which of the following is not multithreading model?
One-to-one
Many-to-one
One-to-many
Many-to-many
5. Page fault occurs when
the page is not in main memory
the page is in main memory
the page enters the block state
the process is in ready state
III/BCA/303 2 Contd.
6. Virtual memory is commonly implemented by
segmentation
swapping
demand paging
page replacement
7. A file is
single-level directory
an abstract data type
tree structure directory
backup and restore
8. There are no cycles in which type of directory?
General graph directory
A cyclic graph directory
One-level directory
Two-level directory
9. Resources are allocated to a process on non-sharable basic in
mutual exclusion
hold and wait
no preemption
circular wait
III/BCA/303 3 Contd.
10. Which of the following is not system threat?
Worm
Port scanning
Denial of service
User card
Indicate whether the following statements are True or False by putting
a Tick mark in the brackets provided 1×5=5
1. A process is the fundamental unit of work in an operating system.
T F
2. Thread is heavy weight.
T F
3. Best fit allocates the first hole that is big enough.
T F
4. Linked allocation solves all problems of contiguous allocation.
T F
5. Viruses need other programs to spread.
T F
III/BCA/303 4 Contd.
SECTION—B
Marks 10
Answer the following questions 2×5=10
1. What are the different operating systems?
2. Compare preemptive scheduling and non-preemptive scheduling.
3. What is translation lookaside buffer
4. What is access control list
5. Define Trojan Horse.
PART B—DESCRIPTIVE
Marks 50
The figures in the margin indicate full marks for the questions
1. What is an operating system? What are the functions performed by it?

Explain single user and batch system in detail. 4
OR
Explain the essential properties of the real time and clustered system
of operating system. 4
Distinguish between multitasking and multiprogramming operating
systems. 6
III/BCA/303 5 Contd.
2. What is a process? With the help of a state transition diagram, explain
the various states of a process.
Define throughput and turnaround time in a multiprogramming
system. 4
OR
Explain the round robin scheduling algorithm with a suitable example. 4
Consider the following set of processes with a length of the CPU burst
time given in milliseconds
Process Burst Time Priority
P1 10 3
P2 1 1
P3 2 4
P4 1 5
P5 5 2
The processes have arrived in the order P1, P2, P3, P4 and P5, all at
time 0.
Draw Gantt charts illustrating the execution of this process using
priority scheduling.
Calculate the average waiting time.
Calculate the average turnaround time. 6
3. What is segmentation? Explain basic segmentation method. 7
Determine the total swap time for a user process of size 10 MB with a
disk transfer rate of 40 MB per second and latency time is 12 msec. 3
OR
Explain process creation. 4
Discuss demand paging in memory management. 6
III/BCA/303 6 Contd.
4. Briefly explain about single-level, two-level and tree structured
directories. 10
OR
What is file protection? Explain the different types of access control. 10
5. What is deadlock? What are the necessary conditions for a deadlock
situation? 6
Describe a resource allocation graph. 4
OR
Explain the safe and unsafe states for deadlock. 4
Consider the following snapshot of a system
Process Allocation Max Available
A B C D A B C D A B C D
P0 0 0 1 2 0 0 1 2 1 5 2 0
P1 1 0 0 0 1 7 5 0
P2 1 3 5 4 2 3 5 6
P3 0 6 3 2 0 6 5 2
Answer the following questions using the Banker's algorithm
What is the content of the matrix Need?
Is the system in a safe state?
If a request from process P1 arrives for can the request
be granted immediately? 6