Circular wait ? In dead lock.

 Set of processer are waiting for each other in a circular fashion. 

For eg= there are 3 processes p0,p1,p2 

Such that p0 is waiting for the resource held by process p1 and process p1 is waiting for the resource held by process p2 and further process p2 is waiting for the resource held by p0.

Methods of handling deadlock 

1 Deadlock Prevention.

2 Deadlock Avoidence.

3 Deadlock Detection and Resolution.

Deadlock Prevention.

= It ensures that the four condition for resource deadlock do not occur simultaneously. This can be done by following methods:

(i) We only use the lock for non-shareable resources and if the resource is shareable then we will not use the lock here.

(ii) That ensures in case of shareable resources, multiple process can access it at same time.

Problem:-

= Here the problem is that we can only do it in case of no-shareable resources like printer we can have use mutual exclusion.