Unit 3: Process Synchronization | Threads
What is the primary challenge addressed by the Critical Section Problem in process synchronization?
A. Allocating memory to processes
B. Managing input/output operations
C. Ensuring exclusive access to shared resources
D. Distributing CPU time among multiple processes
Answer: C. Ensuring exclusive access to shared resources
Explanation: The Critical Section Problem involves ensuring that when multiple processes are running concurrently, only one process can access the shared resources at any given time, thus preventing race conditions.What is the purpose of a semaphore in the context of process synchronization?
A. Allocating memory to processes
B. Controlling access to hardware resources
C. Handling inter-process communication
D. Ensuring exclusive access to shared resources
Answer: D. Ensuring exclusive access to shared resources
Explanation: Semaphores are synchronization tools that allow controlling access to shared resources. They help avoid conflicts by ensuring that only one process can access the resource at a time.In the context of concurrent processes, what are cooperating processes?
A. Processes that do not share any resources
B. Processes that share the same memory space
C. Processes that execute independently
D. Processes that are waiting for I/O operations
Answer: B. Processes that share the same memory space
Explanation: Cooperating processes are those that can share data or resources through shared memory, enabling them to work together in a coordinated manner.What is the role of a precedence graph in process synchronization?
A. Controlling access to hardware resources
B. Representing the order in which processes were created
C. Modeling dependencies among processes
D. Allocating memory to processes
Answer: C. Modeling dependencies among processes
Explanation: A precedence graph is used to represent the relationships and dependencies between processes. It helps in determining the order of execution for processes to avoid conflicts and deadlocks.In the context of process synchronization, what is the purpose of the Hierarchy of Processes?
A. Determining the priority of processes
B. Controlling access to hardware resources
C. Representing the order in which processes were created
D. Managing inter-process communication
Answer: B. Controlling access to hardware resources
Explanation: The Hierarchy of Processes is used to structure processes and manage their access to hardware resources effectively, ensuring proper synchronization and preventing conflicts between processes.
What is a Monitor in the context of process synchronization?
A. A visual representation of the CPU scheduler
B. A hardware primitive for synchronization
C. A high-level abstraction that encapsulates shared data and operations
D. A tool for debugging concurrent processes
Answer: C. A high-level abstraction that encapsulates shared data and operations
Explanation: A Monitor is a synchronization construct that allows safe access to shared resources by encapsulating shared data and the methods that operate on the data, thus providing a mechanism to manage concurrent processes.What classic synchronization problem involves a group of philosophers sitting around a dining table, each thinking and eating with chopsticks?
A. Critical Section Problem
B. Reader-Writer Problem
C. Dining Philosopher Problem
D. Producer-Consumer Problem
Answer: C. Dining Philosopher Problem
Explanation: The Dining Philosopher Problem is a classic synchronization problem that involves multiple philosophers sharing chopsticks while trying to avoid deadlocks and resource contention.In the Reader-Writer Problem, what type of access is exclusive to writers?
A. Read access
B. Write access
C. Both read and write access
D. No access
Answer: B. Write access
Explanation: In the Reader-Writer Problem, writers require exclusive write access to the critical section, meaning no readers or other writers can access the resource when a writer is using it.What is the primary challenge addressed by the Producer-Consumer Problem in synchronization?
A. Ensuring exclusive access to shared resources
B. Controlling access to hardware resources
C. Managing input/output operations
D. Coordinating the work of processes
Answer: D. Coordinating the work of processes
Explanation: The Producer-Consumer Problem involves coordinating the processes of producing and consuming shared data to ensure synchronization and prevent race conditions or data inconsistency.What is the classical solution to the Two-Process Critical Section Problem?
A. Semaphore
B. Test-and-Set Instruction
C. Monitor
D. Message Passing
Answer: B. Test-and-Set Instruction
Explanation: The Test-and-Set Instruction is a hardware-supported atomic operation that ensures mutual exclusion for processes trying to enter a critical section, which is a classical solution to the Two-Process Critical Section Problem.In the n-process solution to the Critical Section Problem, what is the significance of the variable 'turn'?
A. It indicates the order in which processes were created
B. It represents the number of processes in the system
C. It specifies which process is allowed to enter the critical section
D. It controls the priority of processes
Answer: C. It specifies which process is allowed to enter the critical section
Explanation: The 'turn' variable is used in the n-process solution to the Critical Section Problem to specify the process that is allowed to enter the critical section, thus ensuring mutual exclusion.What is the purpose of hardware primitives for synchronization in concurrent programming?
A. Coordinating the work of processes
B. Providing a user interface
C. Controlling access to hardware resources
D. Managing input/output operations
Answer: C. Controlling access to hardware resources
Explanation: Hardware primitives are low-level operations that help in controlling access to shared hardware resources, ensuring synchronization between concurrent processes.What is the key characteristic of the Reader-Writer Problem in synchronization?
A. Readers and writers can access the critical section simultaneously
B. Only one reader or writer can access the critical section at a time
C. Readers and writers are not allowed to access the critical section
D. Writers have priority over readers in accessing the critical section
Answer: B. Only one reader or writer can access the critical section at a time
Explanation: The Reader-Writer Problem ensures that only one process, either a reader or a writer, can access the critical section at any given time to avoid data inconsistency.What is the primary goal of the scheduler activations model in multithreading?
A. Maximizing CPU utilization
B. Minimizing response time
C. Coordinating the execution of processes on multiple CPUs
D. Providing a high-level abstraction for synchronization
Answer: A. Maximizing CPU utilization
Explanation: The scheduler activations model is designed to maximize CPU utilization by efficiently coordinating the execution of threads across multiple processors.In multithreading, what is a key advantage of the many-to-one model?
A. Improved parallelism
B. Simplified program design
C. Better utilization of multiple CPUs
D. Enhanced fault tolerance
Answer: B. Simplified program design
Explanation: The many-to-one model simplifies program design by mapping many user-level threads to a single kernel-level thread, making it easier to implement thread management in single-processor systems.What is an example of a threaded program?
A. A text editor that runs in a single thread
B. A web server that handles multiple requests concurrently
C. A compiler that executes sequentially
D. An operating system kernel
Answer: B. A web server that handles multiple requests concurrently
Explanation: A web server that handles multiple requests concurrently is an example of a multithreaded program, where each request is processed by a separate thread to improve responsiveness.What is the primary purpose of the Test-and-Set instruction in synchronization?
A. Allocating memory to processes
B. Providing a user interface
C. Ensuring exclusive access to shared resources
D. Coordinating the work of processes
Answer: C. Ensuring exclusive access to shared resources
Explanation: The Test-and-Set instruction is used to ensure mutual exclusion, allowing only one process to access a shared resource at a time by setting a flag atomically.In the context of process synchronization, what is the purpose of a condition variable?
A. Indicating the order in which processes were created
B. Signaling a change in the state of shared data
C. Allocating memory to processes
D. Providing a high-level abstraction for synchronization
Answer: B. Signaling a change in the state of shared data
Explanation: A condition variable is used in synchronization to allow threads to signal changes in shared data, enabling other threads to react when necessary.What is the key characteristic of the many-to-many model in multithreading?
A. Each thread has its own kernel-level thread
B. Threads are bound to a specific CPU
C. Multiple user-level threads map to a smaller or equal number of kernel-level threads
D. Each process has only one thread
Answer: C. Multiple user-level threads map to a smaller or equal number of kernel-level threads
Explanation: The many-to-many model maps multiple user-level threads to a smaller or equal number of kernel-level threads, balancing flexibility with the efficiency of kernel thread management.In the context of process synchronization, what is the main challenge addressed by the Two-Phase Locking protocol?
A. Ensuring exclusive access to shared resources
B. Coordinating the work of processes
C. Handling inter-process communication
D. Managing input/output operations
Answer: A. Ensuring exclusive access to shared resources
Explanation: The Two-Phase Locking protocol ensures mutual exclusion by requiring that all locks be acquired before any are released, preventing conflicts and ensuring that no process can access a resource while it is locked by another.