The Deadlock Problem


A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set.
    Example
  • System has 2 disk drives.
  • P1 and P2 each hold one disk drive and each needs another one.

    Example
  • semaphores A and B, initialized to 1
P0P1
wait (A);wait(B)
wait (B);wait(A)



Bridge Crossing Example


bridge crossing example
  • Traffic only in one direction.
  • Each section of a bridge can be viewed as a resource.
  • If a deadlock occurs, it can be resolved if one car backs up (preempt resources and rollback).
  • Several cars may have to be backed up if a deadlock occurs.
  • Starvation is possible.





  • Quantitative Aptitude
    Reasoning
    Programming
    Interview