Difference between mutex and semaphore

Mutex and Semaphore

 

Difference Between Mutex and Semaphore

Definition.

Mutex is a program object which allows multiple processes take turns to share the same resource. In contrast, semaphore is a variable used to control access to a common resource by multiple processes in a concurrent system such as a multitasking operating system. Thus, this is the fundamental difference between mutex and semaphore.

Mechanism

Importantly, the main difference between mutex and semaphore is that the mutex is a locking mechanism, while the semaphore is a signaling mechanism.

Type

Besides, the mutex is an object whereas semaphore is an integer variable.

Categorization

Also, mutex has no categorization, while semaphores are categorized as binary and counting semaphores.

Releasing

Furthermore, if the mutex is locked, the process that requests the lock waits until the system releases the lock. On the other hand,  if the semaphore value is 0, the process perform wait() operation until the semaphore becomes greater than 0.

Operations

Moreover, a process uses acquire() and release() to access and release the mutex, whereas process use wait() and signal() to modify semaphore. Hence, this is another difference between a mutex and semaphore.

Conclusion

In brief, mutex and semaphore are two mechanisms to synchronize the functionality of multiple processes. The main difference between mutex and semaphore is that the mutex is a locking mechanism, while the semaphore is a signaling mechanism. Thus, the semaphore is more sophisticated than mutex.