Summary of  Distributed Dead locks

Reviewed by Naveen Nemani

Target Audience: Programmers and the people who want to learn about deadlocks.

Type of Document: Technical Document.

Summary:

             Dead locks occur whenever a multiple systems are competing to access the limited resources and are allowed to acquire and hold a resource thus preventing others from using the resource while the process waits for the other resources.

                   The two main places for deadlocks are processes in operating system and with the transaction in a database. Four conditions must hold for deadlocks to occur

1) Exclusive use: when a process gains access over a resource the process is given exclusive use of that resource.

2) Hold and Wait: The process holds some resources while it waits for other resources to complete its transaction.

3) No Preemption: The process cannot preempt or take away the resources held by another process.

4) Cyclical Wait: Each process waiting for a resource held by next process.

                  The problem of Dead locks can be handled in several ways like prevention, avoidance and detection. prevention guarantees that dead can never happen because of the way the system is structured. The transaction is made to declare the resources it needs for processing a transaction at first only. The major disadvantage is resources are acquired by process because they might be used not because they will be used. Deadlock avoidance the system considers the request for the resources and checks that  the system does not run into deadlock after the allocation of the resources. eg bankers alg

Conclusion:

             The deadlock defines how a system comes to a stand still position and the ways the system resources are made minimal use. The article will be of interest to those who want to learn more about the deadlocks. I would certainly recommend this article who wants to learn about the deadlocks.