Difference between Deadlock Prevention and Deadlock Avoidance in Operating System

When there are several processes in the CPU, deadlock may occur. Each process holds resources while waiting for another process to have resources. It is known as a deadlock condition. A system may come into a deadlock state when mutual exclusion, hold and wait, no pre-emption, and circular wait these four conditions happen at the same time. There are two types of deadlock mechanisms: deadlock prevention and deadlock avoidance.

In this article, you will learn about the difference between Deadlock Prevention and Deadlock Avoidance in the operating system. But before discussing the differences, you must know about Deadlock Prevention and Avoidance.

What is Deadlock Prevention?

A deadlock prevention method assures that at least one of the four deadlock conditions never occurs. In general, deadlock prevention is impossible to implement, and knowing the total number of current resources, availability, and requests is not needed to avoid a deadlock situation. Non-blocking synchronization methods and serializing tokens are two deadlock prevention strategies. Furthermore, resources for deadlock prevention are allocated conservatively.

What is Deadlock Avoidance?

A system is considered safe when all processes may be assigned resources in any order without causing a deadlock. The deadlock avoidance mechanism prevents the system from coming to an unsafe state. The system should be aware of the number of available resources, availability, and requests to prevent the system from entering an unsafe condition.

The Banker's algorithm is the most widely used mechanism to avoid deadlock. It aids in determining a secure path to execute all processes, and it also includes the overall resources and currently requested resources. Aside from deadlock prevention and avoidance, there is also deadlock detection, which detects deadlocks before or after they occur.

Key differences between Deadlock Prevention and Deadlock Avoidance

Here, you will learn about the various key differences between Deadlock Prevention and Deadlock Avoidance. Some main differences between Deadlock Prevention and deadlock Avoidance are as follows:

1. A deadlock prevention method assures that at least one of the four deadlock conditions never occurs. In contrast, the deadlock avoidance mechanism prevents the system from coming to an unsafe state.
2. All resources are requested at once in deadlock prevention. In contrast, the resource requests are manipulated in deadlock avoidance until at least one secure path is found.
3. The knowledge of future process resource requirements is not required for deadlock prevention. On the other hand, deadlock avoidance necessitates an understanding of future process resource requests.
4. The system doesn't need the information on the available resources, the requested resources, or the current resources while prevent deadlock. The system needs information on existing resources, resource requests, and resource availability to determine if the system is safe or unsafe.
5. There are some algorithms in deadlock prevention, including Non-blocking synchronization and serializing tokens algorithms. On the other hand, the most widely used algorithm in deadlock avoidance is Banker's algorithm.
6. A conservative resource allocation method is used to avoid deadlock. In contrast, the technique for allocating resources to avoid deadlock is not conservative.
7. Preemption is more common in deadlock prevention. In contrast, deadlock avoidance doesn't involve preemption.

Head-to-head comparison between Deadlock Prevention and Deadlock Avoidance

Here, you will learn about the head-to-head comparison between Deadlock Prevention and Deadlock Avoidance. Some main differences between the Deadlock Prevention and Deadlock Avoidance are as follows: