In Dijkstra's Semaphore definition, what happens when a process calls the wait(S) or P(S) operation on a counting semaphore whose current value S is 0?
Option A is correct. The wait(S) operation decrements S. If S becomes negative or zero (depending on implementation), the calling process is blocked and added to the semaphore queue until another process calls signal(S).
What is a major performance downside of using a Spinlock for mutual exclusion on single-processor systems?
Option B is correct. A Spinlock requires a process to continuously loop ('busy waiting') while checking if a lock is available. On a single-processor machine, this wastes CPU execution time that could be used by the lock-holding process.
In the Classic Bounded-Buffer (Producer-Consumer) problem using semaphores, what is the role of the 'empty' counting semaphore initialized to N?
Option B is correct. In Bounded-Buffer synchronization, semaphore 'empty' is initialized to buffer size N to count empty slots. The producer executes wait(empty) before inserting data. 'full' is initialized to 0 for the consumer.
What synchronization phenomenon occurs when a high-priority process is indirectly preempted by a lower-priority process holding a shared resource lock needed by a medium-priority process?
Option A is correct. Priority Inversion happens when a higher-priority task is forced to wait for a lower-priority task holding a shared lock, while medium-priority tasks preemption-delay the lower-priority task. Solved by Priority Inheritance.
Which of the following represents the four necessary Coffman conditions that MUST simultaneously hold for a Deadlock to occur?
Option A is correct. Deadlock can occur if and only if four Coffman conditions hold simultaneously: 1. Mutual Exclusion, 2. Hold and Wait, 3. No Preemption, and 4. Circular Wait.