What is a semaphore in operating systems?
a) A variable used to control access to shared resources
b) A type of memory manager
c) A scheduling algorithm for CPU processes
d) A method of accessing file systems
Answer:
a) A variable used to control access to shared resources
Explanation:
A semaphore is a synchronization primitive used to manage concurrent access to shared resources. It can be viewed as a counter that tracks how many processes or threads can access a critical section or a shared resource at a given time.
Semaphores come in two types: binary semaphores (which allow only one process to access the resource) and counting semaphores (which allow a specified number of processes to access the resource). Semaphores help prevent race conditions, ensuring proper synchronization between processes.
Semaphores are crucial in operating systems for managing concurrency and preventing deadlocks in scenarios where multiple processes or threads need access to shared resources.