Os Process Management Questions Long
A deadlock is a situation in which two or more processes are unable to proceed because each is waiting for the other to release a resource. The necessary conditions for a deadlock to occur are as follows:
1. Mutual Exclusion: At least one resource must be non-sharable, meaning that only one process can use it at a time. This condition ensures that once a process acquires a resource, no other process can access it until it is released.
2. Hold and Wait: A process must be holding at least one resource while waiting to acquire additional resources. This condition ensures that a process can request resources while still holding onto the resources it has already acquired.
3. No Preemption: Resources cannot be forcibly taken away from a process. A process can only release a resource voluntarily. This condition ensures that a process cannot be interrupted and have its resources forcibly taken away, which could potentially lead to deadlock.
4. Circular Wait: There must exist a circular chain of two or more processes, where each process is waiting for a resource held by the next process in the chain. This condition ensures that there is a dependency loop among the processes, leading to a deadlock situation.
If all these conditions are satisfied simultaneously, a deadlock can occur. It is important to note that the absence of any one of these conditions can prevent a deadlock from happening. Therefore, to prevent deadlocks, operating systems employ various techniques such as resource allocation strategies, deadlock detection algorithms, and resource scheduling policies.