***What is a Deadlock?
A deadlock occurs when two or more processes become stuck because they are each waiting for the other to release a resource. In other words, they are waiting for an event that will never happen, resulting in a standstill. This situation is called a deadlock.

Necessary Conditions for Deadlock
For a deadlock to occur, four conditions must be true simultaneously:

Mutual Exclusion:
Only one process can use a resource at a time.
If another process requests that resource, it must wait until the resource is released.

Hold and Wait:
A process is holding at least one resource and waiting to acquire additional resources held by other processes.

No Preemption:
Resources cannot be forcibly taken away from a process.
A resource can only be released voluntarily by the process holding it.

Circular Wait:
There is a circular chain of processes, each waiting for a resource that the next process in the chain holds.

Methods to Handle Deadlocks

1. Deadlock Ignorance (Ostrich Method):
   The system pretends that deadlocks do not exist.
   This method is often used because deadlocks occur infrequently.
   Handling deadlocks can decrease system performance, so the cost of dealing with them is often higher than ignoring them.

2)Deadlock Prevention:
This approach prevents one or more of the necessary conditions from occurring.
To prevent deadlocks, one or more of the following conditions must be made false:

Mutual Exclusion: Allow multiple processes to use a resource simultaneously (not always possible).

Hold and Wait: Require processes to request all resources at once or release held resources before requesting more.

No Preemption: Allow the system to forcibly take resources from processes.

Circular Wait: Impose a linear order of resource types and ensure that processes request resources in increasing order.

3. Deadlock Avoidance:
   This approach allows the system to allocate resources only if doing so does not lead to an unsafe state.
   The Banker's Algorithm is a popular method used for deadlock avoidance.
   It evaluates if granting a resource will leave the system in a "safe" state.

4. Deadlock Detection and Recovery:
   This approach allows deadlocks to occur but detects and resolves them.
   Detection: The system periodically checks for cycles in the resource allocation graph or uses a detection algorithm.
   Recovery: After detecting a deadlock, the system can recover by:
   Termination: Terminating one or more processes to break the deadlock.
   Resource Preemption: Forcibly taking resources away from processes.*