Deadlock prevention deadlock avoidance

Deadlock prevention is a set of methods for ensuring that at least one of the four necessary conditions like mutual exclusion, hold and wait, no pre-emption and circular wait cannot hold. By ensuring that that at least one of these conditions cannot hold, the occurrence of a deadlock can be prevented.

An alternative method for avoiding deadlocks is to require additional information about how resources are to be requested. Each request requires the system consider the resources currently available, the resources currently allocated to each process, and the future requests and releases of each process, to decide whether the could be satisfied or must wait to avoid a possible future deadlock.