Quiz 3 - Process Synchronization

The statement is true because locks ensure that only one thread can access a critical region at a time. This prevents race conditions, which occur when multiple threads try to access and modify shared data simultaneously, leading to unpredictable and erroneous results. By using locks, the critical region is protected, and only one thread can enter it at a time, ensuring data integrity and preventing race conditions.

A counting semaphore is a synchronization primitive that allows multiple threads to access a shared resource. Unlike a binary semaphore, which can only have two states (0 and 1), a counting semaphore can have any non-negative integer value. Therefore, the given statement that the value of a counting semaphore can range only between 0 and 1 is incorrect.

A solution to the critical section problem must satisfy the requirements of mutual exclusion, bounded waiting, and progress. Atomicity, however, is not a requirement for a solution to the critical section problem. Atomicity refers to the property that an operation is indivisible or uninterruptible. While atomicity can be desirable in certain situations, it is not necessary for a solution to the critical section problem.

A counting semaphore is essentially an integer variable because it is used to control access to a shared resource by multiple threads. It maintains a count of the number of available resources and allows or blocks access based on this count. The value of the semaphore is an integer that is incremented or decremented by the threads as they acquire or release the resource.

Mutex locks and counting semaphores are not essentially the same thing. While both are synchronization mechanisms used in concurrent programming, they have different characteristics and purposes. A mutex lock is used to provide exclusive access to a shared resource, allowing only one thread to access it at a time. On the other hand, a counting semaphore is used to control the number of threads that can access a shared resource simultaneously. It maintains a count and allows a specific number of threads to access the resource concurrently. Therefore, the statement that mutex locks and counting semaphores are essentially the same thing is false.

The correct order of operations for protecting a critical section using a binary semaphore is to first wait for the semaphore (wait()), which blocks the process if the semaphore value is 0, ensuring mutual exclusion. Then, once the critical section is completed, the process signals the semaphore (signal()), allowing other processes to enter the critical section. This order ensures that only one process can enter the critical section at a time, preventing race conditions and ensuring synchronization.

A race condition occurs when several threads try to access and modify the same data concurrently. In this situation, the outcome of the execution may be unpredictable and inconsistent because the threads may interfere with each other's operations. This can lead to errors and bugs in the program.

A mutex lock is essentially a boolean variable because it can have two states: locked or unlocked. When a thread wants to access a critical section of code, it checks the state of the mutex lock. If it is unlocked, the thread locks it and proceeds with the execution. If it is already locked, the thread waits until it becomes unlocked. This behavior is similar to a boolean variable where true represents locked and false represents unlocked.