Use of semaphore

Question

What is Semaphore and when we using this? will

Answer 1

Semaphore is used to ignore the effect of dead lock. There are three kind of semaphore.

1) Binary semaphore-> this is only to obtain and release the semaphore. Zero is used for unavailable and one is utilized for available.

2) Counting semaphore-> While semaphore is got counter is incremented and while semaphore is released conter is decremented. While counter is zero it is goes to blocked state.

3) Mutual exclusion-> it is similar as binary semaphore. But it is utilized for safety reason. It is two state locked state and unlocked state. While semaphore is got it is goes to locked state and while semaphore is released it goes to unlocked state.