What is Mutex vs. Semaphore in operating systems?

What is Mutex?

Mutex stands for Mutual Exclusion Object. Mutex is a particular kind of binary semaphore that is applied to control access to the share. Mutex involves a priority inheritance method to avoid advanced priority inversion difficulties.

Mutex allows current tasks with a higher priority to be kept in a locked state for the shortest possible time. However, priority inheritance does not correct the priority inversion; it only reduces its effect.

Why do we need Mutex?

A Mutex implements a mutual exclusion between a producer or consumer, which can hold the key (i.e. Mutex) and continue its job.

While the producer fills the buffer, the user must wait, and vice versa. In Mutex locking, only one thread can handle the whole buffer at a time.

Advantages of Mutex

Below are some of the advantages of Mutex.

What is Semaphore?

Semaphore is an integer variable that is commonly used by threads for process synchronization.

A Semaphore is a signaling method. A thread expecting a Semaphore can be signaled by the other thread.

A Semaphore uses two atomic processes:

1. Wait

2. Signal for process synchronization

A Semaphore permits or denies access to the resource, depending on how it is configured.

Why do we need Semaphore?

For a particular buffer, we can divide the 4KB buffer into four 1KB buffers. A Semaphore can be assigned to these four buffers, which enables users and producers to operate on separate buffers at the same time.

Advantages of Semaphore

Let’s take a look at some of the benefits of Semaphore below.

Mutex vs. Semaphore

Below are some of the main differences between Mutex and Semaphore.