The difference between the signal volume and the mutex and the critical area

Semaphores can be obtained and released by arbitrary threads throughout the system, that is, the same semaphore can be obtained by one thread in the system and then released by another thread. The mutex requires which thread acquires the mutex, which thread is responsible for releasing, and the other threads are not valid for releasing the mutex.

Mutexes and semaphores are visible in any process of the system, that is, a process creates a semaphore or mutex, and another process attempts to acquire the lock is legal. However, the scope of the critical section is limited to this process, and other processes cannot acquire the lock. In addition, the critical section has the same properties as the mutex.

The difference between the signal volume and the mutex and the critical area