Operating System
Exam Duration: 45 Mins Total Questions : 30
In time-sharing operating system, when time slot given to a process is completed, the process goes from the running state to the
- (a)
blocked state
- (b)
dead state
- (c)
suspended state
- (d)
terminated state
Some computer system supports dual mode operations, the user mode and the supervisor mode. These refers to the modes
- (a)
by which user program handle their data
- (b)
by which operating system executes its program
- (c)
in which the processor and the associated hardware operate
- (d)
of memory access
In Round-Robin CPU scheduling, as the time quantum is increased, the average turn around time
- (a)
increases
- (b)
decreases
- (c)
remains constant
- (d)
varies irregularly
Round-Robin scheduling is essentially the primitive version of
- (a)
FIFO
- (b)
shortest job first
- (c)
shortest remaining time first
- (d)
longest time first
Which of the following statements is true?
1. Shortest remaining time first scheduling may cause starvation
2. Pre-emptive scheduling may cause starvation
3. Round-Robin is better than FCFS in terms of response time
- (a)
1 only
- (b)
1 and 3
- (c)
2 and 3
- (d)
1, 2 and 3
A critical region
- (a)
is a piece of code which only one process executes at a time
- (b)
is a region prone to deadlock
- (c)
is a piece of code which only a finite number of process executes
- (d)
None of the above
A thread is a _____ process.
- (a)
heavy weight
- (b)
multi process
- (c)
intertread
- (d)
light weight
Consider the following statements with respect to user clever threads and kernel with kernal supported threads:
1. Context switch is faster with Kernal supported threads
2. For user-level threads, a system call can block the entire process
3. Kernal supported threads can be scheduled independently
4. User level threads are transparent to the kernal.
Which of the above statement is true?
- (a)
1, 2, 4
- (b)
2, 3
- (c)
1 and 3
- (d)
1 and 2
Supervisor call
- (a)
ia a call made by the supervisor of the system
- (b)
is a call with control function
- (c)
is a call made by someone working in root directory
- (d)
None of the above
With a single resource, deadlock occurs
- (a)
If there are more than two processes competing for that resource
- (b)
If there are only two processes competing for that resource
- (c)
If there is a single process competing for that resource
- (d)
None of the above
Mutual exclusion is a problem occurs between
- (a)
two disjoint process that do not interact
- (b)
process that share resources
- (c)
processes that do not use the some resources
- (d)
None of the above
A single process system has three resource type X, Y and Z which are shared by the three processes. There are 5 units of each resource types. Consider the following scenario, where the column also denotes the number of units of each resource type allocated to each process and the column request denotes the number of units of the type of each resource requested by a process in under to the execution. Which of these processes will finish?
Alloc
X | Y | Z | |
Po | 1 | 2 | 1 |
P1 | 2 | 0 | 1 |
P2 | 2 | 2 | 1 |
Request
X | Y | Z |
1 | 0 | 3 |
0 | 1 | 2 |
1 | 2 | 0 |
- (a)
P0
- (b)
P1
- (c)
P2
- (d)
None of the above
The first fit best fit and worst-fit algorithm can be used for
- (a)
contiguous memory location
- (b)
linked allocation of memory
- (c)
index allocation of memory
- (d)
All of the above
Which of the following statement is false?
- (a)
Segmentation suffers from external fragmentation
- (b)
Paging suffers from internal fragmentation
- (c)
Segmented memory can be paged
- (d)
Virtual memory is used only in multi user system
_____ page replacement algorithm suffers from Belad'y.
- (a)
LRU
- (b)
MRU
- (c)
FIFO
- (d)
LIFO
The essential contents in each entry of a page table is/are
- (a)
virtual page number
- (b)
page frame number
- (c)
both virtual page number and page frame number
- (d)
access right information
A system uses FIFO policy for page replacement. It has 4 page frames with no pages loaded to begin with. The system first accesses 100 distinct page in same order and then accesses the same 100 page but now in the reverse order. How many page fault will occur?
- (a)
196
- (b)
192
- (c)
197
- (d)
195
The simple directly structure is
- (a)
single level directory
- (b)
two level directory
- (c)
tree level directory
- (d)
None of the above
There are no cycle in which type of directory
- (a)
general graphic directory
- (b)
a cyclic graph directory
- (c)
one level directory
- (d)
two level directory
Supervisor stage is
- (a)
entered by programs when they enter the processor
- (b)
required to perform any I/O
- (c)
only allowed to the operating system
- (d)
never used
Multiprogramming systems
- (a)
are easier to develop than single programming systems
- (b)
execute each job faster
- (c)
execute more jobs in the same time
- (d)
are used only on large main frame computers
The number of processes completed per unit time is known as
- (a)
output
- (b)
throughout
- (c)
efficiency
- (d)
capacity
______ is the situation in which a process is waiting on another process which is also waiting on another process ______ which is waiting on the first process. None of the processes involved in this circular wait are making progress.
- (a)
deadlock
- (b)
starvation
- (c)
dormant
- (d)
None of these
A critical region
- (a)
is a piece of code which only one process executes at a time
- (b)
is a region prone to deadlock
- (c)
is a piece of code which only a finite number of processes execute
- (d)
is found only in Windows NT operating system
Switching the CPU to another process requires to save state of the old process and loading new process state is called as
- (a)
process blocking
- (b)
context switching
- (c)
time sharing
- (d)
None of these
Which directory implementation is used in the most Operating system?
- (a)
Single level directory structure
- (b)
Two level directory structure
- (c)
Tree directory structure
- (d)
A cyclic directory structure
Using priority scheduling algorithm, find the average waiting time for the following set of process given with their priorities in the order, process, Burst Time, priority, respectively.
\({ P }_{ 1 }:10:3\\ { P }_{ 2 }:1:1,\\ { P }_{ 3 }:1:1,\\ { P }_{ 4 }:1:5,\\ { P }_{ 5 }:5:2.\)
- (a)
8 ms
- (b)
8.2 ms
- (c)
7.75 ms
- (d)
3 ms
A binary semaphore
- (a)
has the values one or zero
- (b)
is essential to binary computers
- (c)
is used only for synchronisation
- (d)
is used only for mutual exclusion
_____ is a high-speed cache used to hold recently referenced page table entries a part of paged virtual memory
- (a)
Translation lookaside buffer
- (b)
Inverse page table
- (c)
Segmented page table
- (d)
All of the above
The problem of thrashing is effected scientifically by
- (a)
program structure
- (b)
program size
- (c)
primary storage size
- (d)
None of these