Deadlock Avoidance and Prevention in OS

Deadlock avoidance in OS

Deadlock avoidance is a technique used in operating systems to prevent the situation where two or more processes are unable to proceed because each is waiting for one of the others to release a resource. Unlike deadlock prevention, which uses static information to prevent a deadlock from occurring, deadlock avoidance uses dynamic information, such as the current state of the system and the resource allocation, to ensure that a deadlock never occurs. Some common methods of deadlock avoidance include:

1. Wait/Die: In this method, a process that requests a resource that is not available will wait until the resource becomes available. If a process that holds the resource is also requesting a resource that is not available, the process that has been waiting the longest will be allowed to proceed.

2. Wound/Wait: In this method, a process that requests a resource that is not available will be killed (wounded) if a process that holds the resource is also requesting a resource that is not available. The process that was killed will have to request the resource again later.

3. Resource allocation graph: By representing the resources and the processes as nodes in a graph, the operating system can use algorithms to check for safe states before allocating resources.

4. Banker’s Algorithm: This algorithm is a variant of Resource Allocation Graph algorithm, it uses the available and maximum resource information for each process, the algorithm checks for safe state before allocating resources.

5. Time-stamp ordering: In this method, a process is only allowed to request a resource if its time stamp is greater than the time stamp of the process that holds the resource.

These are some of the common methods used in operating systems for deadlock avoidance. The best method to use depends on the specific requirements of the system and the resources being used.