Unit -2

Question 1

What is a thread in the context of operating systems?

Answer 1

A thread is the smallest unit of processing that can be scheduled by an operating system.

Question 2

True or False: A process can contain multiple threads.

Answer 2

True

Question 3

What is multithreading?

Answer 3

Multithreading is the ability of a CPU or a single core to provide multiple threads of execution concurrently.

Question 4

Fill in the blank: The _______ is responsible for managing threads in an operating system.

Answer 4

scheduler

Question 5

What are the two types of thread management?

Answer 5

User-level threads and kernel-level threads.

Question 6

What is the primary advantage of multithreading?

Answer 6

It allows for more efficient CPU usage and improved application performance.

Question 7

Multiple Choice: Which of the following is NOT a scheduling type? A) Preemptive B) Cooperative C) Iterative D) Time-slicing

Answer 7

C) Iterative

Question 8

What does preemptive scheduling allow the operating system to do?

Answer 8

It allows the operating system to interrupt a currently running thread to start or resume another thread.

Question 9

True or False: Cooperative scheduling relies on threads to voluntarily yield control.

Answer 9

True

Question 10

What is a critical section in multithreading?

Answer 10

A critical section is a part of the code that accesses shared resources and must not be executed by more than one thread at a time.

Question 11

What is a context switch?

Answer 11

A context switch is the process of storing the state of a thread so it can be resumed later.

Question 12

Fill in the blank: The _______ algorithm allocates CPU time to threads based on their priority.

Answer 12

priority scheduling

Question 13

What is the purpose of thread synchronization?

Answer 13

To ensure that multiple threads can operate safely on shared data without conflict.

Question 14

Multiple Choice: Which of the following is a common synchronization mechanism? A) Mutex B) Semaphore C) Lock D) All of the above

Answer 14

D) All of the above

Question 15

What is starvation in the context of thread scheduling?

Answer 15

Starvation occurs when a thread is perpetually denied the resources it needs to proceed with execution.

Question 16

True or False: Round-robin scheduling is a type of preemptive scheduling.

Answer 16

True

Question 17

What is the main objective of a scheduling algorithm?

Answer 17

To allocate CPU time effectively among multiple threads or processes.

Question 18

Fill in the blank: In a _______ environment, multiple processors are used to execute multiple threads simultaneously.

Answer 18

multiprocessor

Question 19

What is load balancing in multiprocessor systems?

Answer 19

Load balancing is the process of distributing workloads across multiple processors to optimize resource use and minimize response time.

Question 20

Multiple Choice: Which scheduling algorithm is designed for real-time systems? A) FIFO B) Round Robin C) Rate Monotonic D) Shortest Job First

Answer 20

C) Rate Monotonic

Question 21

What is the definition of throughput in scheduling?

Answer 21

Throughput is the number of processes completed in a given amount of time.

Question 22

What is latency in the context of thread scheduling?

Answer 22

Latency is the time taken from the submission of a process until its first execution.

Question 23

True or False: A thread can exist without a process.

Answer 23

False

Question 24

What is a thread pool?

Answer 24

A thread pool is a collection of pre-initialized threads that can be reused for executing tasks.

Question 25

Fill in the blank: _______ allows threads to run concurrently, but not necessarily in parallel.

Answer 25

Multithreading

Question 26

What does the term 'context' refer to in the context of threads?

Answer 26

Context refers to the current state of a thread, including its registers, stack, and program counter.

Question 27

Multiple Choice: Which of the following is a disadvantage of multithreading? A) Increased resource sharing B) Complexity in debugging C) Improved performance D) Better resource utilization

Answer 27

B) Complexity in debugging

Question 28

What is the difference between user-level threads and kernel-level threads?

Answer 28

User-level threads are managed by the user-level library, while kernel-level threads are managed by the operating system.

Question 29

True or False: Kernel-level threads can be scheduled independently by the operating system.

Answer 29

True

Question 30

What is a semaphore?

Answer 30

A semaphore is a synchronization primitive that uses a counter to control access to shared resources.

Question 31

Fill in the blank: _______ scheduling can lead to better average turnaround time compared to other types.

Answer 31

Shortest Job First

Question 32

What is a deadlock in multithreading?

Answer 32

A deadlock is a situation where two or more threads are unable to proceed because they are each waiting for the other to release resources.

Question 33

What is a race condition?

Answer 33

A race condition occurs when two or more threads attempt to change shared data at the same time, leading to inconsistent results.

Question 34

True or False: A multiprocessor system can improve performance by executing multiple threads in parallel.

Answer 34

True

Question 35

What does 'scalability' refer to in a multiprocessor environment?

Answer 35

Scalability refers to the ability to increase performance by adding more processors.

Question 36

Fill in the blank: _______ is a scheduling criterion that aims to minimize the waiting time for processes.

Answer 36

Shortest Job First

Question 37

What is the main disadvantage of preemptive scheduling?

Answer 37

It can lead to increased overhead due to context switching.

Question 38

Multiple Choice: Which scheduling algorithm is most likely to cause starvation? A) Round Robin B) Priority Scheduling C) Shortest Job First D) First-Come, First-Served

Answer 38

B) Priority Scheduling

Question 39

What is the purpose of a mutex?

Answer 39

A mutex is used to ensure that only one thread can access a resource at a time.

Question 40

True or False: All threads within a process share the same address space.

Answer 40

True

Question 41

What is time-slicing in scheduling?

Answer 41

Time-slicing is a technique where each thread is given a small time slot to execute before the next thread is scheduled.

Question 42

Fill in the blank: The _______ algorithm is designed to ensure that all processes receive fair share of CPU time.

Answer 42

Round Robin

Question 43

What is a thread-safe function?

Answer 43

A thread-safe function is one that can be safely called from multiple threads at the same time without causing data corruption.

Question 44

Multiple Choice: Which of the following is NOT a scheduling criterion? A) Turnaround Time B) Response Time C) Memory Usage D) Throughput

Answer 44

C) Memory Usage

Question 45

What is the role of the dispatcher in thread scheduling?

Answer 45

The dispatcher is responsible for switching the CPU from one thread to another.

Question 46

True or False: Threads can communicate with each other through shared memory.

Answer 46

True

Question 47

What is the difference between soft real-time and hard real-time systems?

Answer 47

Hard real-time systems must meet deadlines, while soft real-time systems aim to meet deadlines but can tolerate some delays.

Question 48

Fill in the blank: A _______ is a high-level abstraction that represents a thread of execution.

Answer 48

task

Question 49

What is the main goal of scheduling algorithms?

Answer 49

To optimize CPU utilization and ensure fair allocation of resources among processes.

Question 50

Multiple Choice: What does the term 'multi-core' refer to? A) Multiple CPUs B) Multiple threads C) Multiple cores in a single CPU D) None of the above

Answer 50

C) Multiple cores in a single CPU

Question 51

What is the effect of thread contention?

Answer 51

Thread contention occurs when multiple threads compete for the same resources, which can lead to decreased performance.

Question 52

True or False: All operating systems support multithreading.

Answer 52

False

Question 53

What does the term 'load sharing' mean in a multiprocessor environment?

Answer 53

Load sharing refers to the distribution of workloads across multiple processors to improve performance.

Question 54

Fill in the blank: The _______ algorithm selects processes based on their predicted execution time.

Answer 54

Shortest Job First

Question 55

What is the role of a thread library?

Answer 55

A thread library provides the necessary functions and interfaces for creating and managing threads.

Question 56

Multiple Choice: Which type of thread is managed entirely by the user-level library? A) Kernel thread B) User thread C) Hybrid thread D) None of the above

Answer 56

B) User thread

Question 57

What does 'fairness' refer to in scheduling?

Answer 57

Fairness refers to the equitable allocation of CPU time among all processes.

Question 58

True or False: A thread can be suspended and resumed at will.

Answer 58

True

Question 59

What is the purpose of a condition variable?

Answer 59

A condition variable allows threads to wait for certain conditions to be true before proceeding.

Question 60

Fill in the blank: In a _______ scheduling policy, each process is assigned a fixed time slice for execution.

Answer 60

time-sharing

Question 61

What is the significance of priority in scheduling?

Answer 61

Priority determines the order in which threads are scheduled for execution.

Question 62

Multiple Choice: Which of the following is a disadvantage of cooperative scheduling? A) Increased responsiveness B) Possibility of starvation C) Simplicity D) All of the above

Answer 62

B) Possibility of starvation