1.
What is a
page fault in the context of demand paging?
•
Options:
(a) A
page that contains errors and cannot be used
(b) A
page that is too large to fit into memory
(c)
A reference to a page that is not currently in main
memory
(d) A
page that has been marked as read-only
•
Correct
Answer: (c) A reference to a page that is not currently in main memory
•
Explanation:
A page fault occurs when the CPU tries to access a
page not loaded into main memory, triggering the operating system to load it
from secondary storage.
2.
How many
pages must be present in the main memory for demand paging to work efficiently?
•
Options:
(a) 8192
pages
(b) 4096
pages
(c)
2048 pages
(d) 16384
pages
•
Correct
Answer: (a) 8192 pages
•
Explanation:
Memory required = 32 MB=32×1024×1024
•
Page size = 4 KB=4096 bytes
Number of pages required = 32×1024×10244096=8192 pages
3.
Message
passing system allows processes to:
•
Options:
(a) communicate
with one another without resorting to shared data
(b) communicate
with one another by resorting to shared data
(c)
share data
(d) name
the recipient or sender of the message
•
Correct
Answer: (a) communicate with one another without resorting to shared data
•
Explanation:
Message passing is an IPC mechanism where processes
exchange messages directly without needing shared memory.
4.
The link
between two processes P and Q to send and receive messages is called:
•
Options:
(a) communication
link
(b) message-passing
link
(c)
synchronization link
(d) All
of these
•
Correct
Answer: (a) communication link
•
Explanation:
A communication link facilitates the transfer of
messages between processes in an inter-process communication system.
5.
How can
buffer overflow vulnerabilities be mitigated?
•
Options:
(a) By
using large buffer sizes to accommodate more data
(b) By
disabling all security mechanisms
(c)
By relying solely on antivirus software
(d) By
implementing input validation and using safe coding practices
•
Correct
Answer: (d) By implementing input validation and using safe coding
practices
•
Explanation:
Input validation ensures data is within expected
bounds, and safe coding prevents excessive data from overflowing a buffer.
6.
Which
programming languages are particularly susceptible to buffer overflow
vulnerabilities?
•
Options:
(a) Only
low-level languages like C and Assembly
(b) Only
high-level languages like Python and Java
(c)
Both low-level and high-level languages
(d) Buffer
overflows are not language-dependent
•
Correct
Answer: (a) Only low-level languages like C and Assembly
•
Explanation:
Low-level languages like C and Assembly are more
prone because they lack built-in bounds checking, unlike high-level languages.
7.
Which file
access method allows data to be read or written randomly, without the need for
sequential access?
•
Options:
(a) Sequential
access
(b) Direct
access
(c)
Serial access
(d) Shared
access
•
Correct
Answer: (b) Direct access
•
Explanation:
Direct access allows data to be read or written at
any location without requiring sequential traversal.
8.
In which
allocation method is the file represented by a table containing pointers to its
blocks scattered throughout the disk?
•
Options:
(a) Contiguous
allocation
(b) Linked
allocation
(c)
Indexed allocation
(d) Dynamic
allocation
•
Correct
Answer: (c) Indexed allocation
•
Explanation:
In indexed allocation, a table of pointers is used
to store the locations of blocks, enabling scattered storage.
9.
What is
demand paging in operating systems?
•
Options:
(a) A
paging technique that swaps entire processes in and out of memory
(b) A
paging technique that preloads all pages of a process into memory
(c)
A paging technique that brings in pages only when they
are required
(d) A
technique that eliminates the need for virtual memory
•
Correct
Answer: (c) A paging technique that brings in pages only when they are
required
•
Explanation:
Demand paging loads pages into memory only when
they are needed, minimizing memory usage.
10.
In swapping,
what is moved between main memory and secondary storage?
•
Options:
(a) Data
files
(b) Operating
system files
(c)
Entire processes
(d) CPU
registers
•
Correct
Answer: (c) Entire processes
•
Explanation:
Swapping moves entire processes between main memory
and secondary storage to manage memory efficiently.
11.
What type of
device allows data to be read or written in a linear sequence and is commonly
used for magnetic tapes?
•
Options:
(a) Serial
access device
(b) Direct
access device
(c)
Virtual device
(d) Shared
device
•
Correct
Answer: (a) Serial access device
•
Explanation:
Serial access devices access data sequentially,
making them ideal for magnetic tapes.
12.
Which IPC
mechanism allows two processes to communicate by reading from and writing to a
shared data stream?
•
Options:
(a) Pipes
(b) Semaphores
(c)
Message queues
(d) Shared memory
Correct Answer: (a) Pipes
•
Explanation:
Pipes enable communication between processes by
creating a shared data stream.
13.
What is a
potential drawback of applying strict mutual exclusion in a multithreaded
program?
•
Options:
(a) Increased
performance and efficiency
(b) Deadlocks
and contention
(c)
Improved scalability
(d) Reduced synchronization overhead
Correct Answer: (b) Deadlocks and contention
•
Explanation:
Strict mutual exclusion can cause deadlocks and
contention when multiple threads wait indefinitely for resources.
14.
In a
multi-threaded application, how is mutual exclusion typically achieved?
•
Options:
(a) By
allowing all threads to simultaneously access shared resources.
(b) By
using locks, mutexes, or semaphores to protect critical sections.
(c)
By using a round-robin scheduling algorithm
(d) By
assigning different priority levels to threads
•
Correct
Answer: (b) By using locks, mutexes, or semaphores to protect critical
sections
•
Explanation:
Mutual exclusion is achieved by mechanisms like
locks and semaphores, which ensure only one thread accesses critical resources
at a time.
15.
The logical
address is generated by:
•
Options:
(a) Base
Register
(b) Limit
Register
(c)
CPU
(d) Memory Management Unit
Correct Answer: (c) CPU
•
Explanation:
The CPU generates a logical address, which is
translated to a physical address by the memory management unit (MMU).
16.
Which page
replacement algorithm selects the page that has not been used for the longest
period of time?
•
Options:
(a) FIFO
(First-In-First-Out)
(b) LRU
(Least Recently Used)
(c)
Optimal Page Replacement
(d) Random
Page Replacement
•
Correct
Answer: (b) LRU (Least Recently Used)
•
Explanation:
LRU replaces the page that has been unused for the
longest time, aiming to predict which page is least likely to be accessed soon.
17.
Identify
which one of the following is a synchronization tool:
•
Options:
(a) Semaphore
(b) Thread
(c)
Pipe
(d) Socket
•
Correct
Answer: (a) Semaphore
•
Explanation:
Semaphores are synchronization tools used to manage
access to shared resources.
18.
What is the
primary purpose of a directory in a file system?
•
Options:
(a) To
store data files
(b) To
organize and manage files
(c)
To allocate disk space
(d) To
perform file I/O operations
•
Correct
Answer: (b) To organize and manage files
•
Explanation:
Directories provide a structure to organize and
manage files for easy access and retrieval.
19.
A problem
encountered in multitasking when a process is perpetually denied necessary
resources is called:
•
Options:
(a) Deadlock
(b) Starvation
(c)
Inversion
(d) Aging
•
Correct
Answer: (b) Starvation
•
Explanation:
Starvation occurs when a process waits
indefinitely for resources due to priority scheduling favoring other processes.
20.
Which one of
the following is a visual (mathematical) way to determine deadlock occurrence?
•
Options:
(a) Resource
allocation graph
(b) Starvation
graph
(c)
Inversion graph
(d) None
of the mentioned
•
Correct
Answer: (a) Resource allocation graph
•
Explanation:
A resource allocation graph visually represents
processes and resource dependencies to detect potential deadlocks.
21.
In
segmentation, what is the logical address composed of?
•
Options:
(a) A
page number and an offset within the page
(b) A
segment number and an offset within the segment
(c)
A block number and an offset within the block
(d) A
memory address and a register value
•
Correct
Answer: (b) A segment number and an offset within the segment
•
Explanation:
Segmentation divides memory into variable-sized
segments, and logical addresses consist of a segment number and an offset
within that segment.
22.
In a
computer system using segmentation, the logical address consists of a segment
number (10 bits) and an offset within the segment (12 bits). Calculate the
maximum size of each segment:
•
Options:
(a) 2
KB
(b) 4
KB
(c)
8 KB
(d) 16
KB
•
Correct
Answer: (b) 4 KB
•
Explanation:
The offset size determines the maximum segment size:
2^12=4096
•
bytes=4
23.
Consider a
paging hardware with a TLB. Assume that the entire page table and all the pages
are in the physical memory. It takes 10 milliseconds to search the TLB and 90
milliseconds to access the physical memory. If the TLB hit ratio is 0.6, the
effective memory access time (in milliseconds) is:
•
Options:
(a) 122
(b) 136
(c)
280
(d) 118
•
Correct
Answer: (b) 136
•
Explanation:
Effective memory access time (EMAT) is calculated
as:
EMAT=(Hit Ratio×TLB Time)+(Miss Ratio×(TLB Time+Memory Time))
Substitute values:
EMAT=(0.6×90)+(0.4×(10+90))=136 ms
24.
The logical
address generated by the CPU is compared with the limit of the process. If the
address is found to be greater than or equal to the limit, then:
•
Options:
(a) Relocation
register value is added
(b) Trap
is generated
(c)
Logical address is never compared with limit register
(d) None
of the mentioned
•
Correct
Answer: (b) Trap is generated
•
Explanation:
If the logical address exceeds the limit, a trap is
generated to signal an illegal memory access.
25.
Which of the
following condition is required for a deadlock to be possible?
•
Options:
(a) Mutual
exclusion
(b) A
process may hold allocated resources while awaiting assignment of other
resources
(c)
No resource can be forcibly removed from a process
holding it (d) All of the mentioned
•
Correct
Answer: (d) All of the mentioned
•
Explanation:
The four necessary conditions for deadlock are:
mutual exclusion, hold and wait, no preemption, and circular wait.
26.
For an
effective operating system, when to check for deadlock?
•
Options:
(a) Every
time a resource request is made
(b) At
fixed time intervals
(c)
Every time a resource request is made and at fixed time
intervals (d) None of the mentioned
•
Correct
Answer: (c) Every time a resource request is made and at fixed time
intervals
•
Explanation:
Checking for deadlocks continuously and
periodically ensures that the system can handle potential issues promptly.
27.
In indirect
communication between processes P and Q:
•
Options:
(a) There
is another process R to handle and pass on the messages between P and Q
(b) There
is another machine between the two processes to help communication
(c)
There is a mailbox to help communication between P and
Q
(d) None
of the mentioned
•
Correct
Answer: (c) There is a mailbox to help communication between P and Q
•
Explanation:
Indirect communication uses mailboxes or message
queues to facilitate communication without direct connections.
28.
In the
non-blocking send:
•
Options:
(a) The
sending process keeps sending until the message is received
(b) The
sending process sends the message and resumes operation
(c)
The sending process keeps sending until it receives a
message (d) None of these
•
Correct
Answer: (b) The sending process sends the message and resumes operation
•
Explanation:
In non-blocking communication, the sender does not
wait for the receiver to acknowledge the message and continues execution.
29.
Which
condition is responsible for circular wait in the four necessary conditions for
deadlock?
•
Options:
(a) Mutual
exclusion
(b) Hold
and wait
(c)
No preemption
(d) Circular
wait
•
Correct
Answer: (b) Hold and wait
•
Explanation:
Circular wait occurs when a process holds resources
and waits for others held by other processes, completing the cycle.
30.
In the
context of deadlock prevention, what does "preemption" refer to?
•
Options:
(a) Forcing
a process to release its allocated resources
(b) Allowing
a process to wait indefinitely for a resource
(c)
Granting resources to a process immediately upon
request
(d) Terminating
a process to release its resources
•
Correct
Answer: (a) Forcing a process to release its allocated resources
•
Explanation:
Preemption prevents deadlocks by allowing resources
to be forcibly taken from a process to allocate them to others.