OS2: Deadlocks-Unit 2: Methods for Dealing with Deadlocks

As you have seen in the previous unit, for a deadlock to occur, each of the four necessary conditions must hold. You were also introduced to some of the methods for handling a deadlock situation. In this unit you will be fully exposed to deadlock prevention and deadlock avoidance approaches. As discussed before, deadlock prevention is all about ensuring that at least one of the four necessary conditions cannot hold, we will elaborate further by examining each of the four conditions separately. Deadlock avoidance is an alternative method for avoiding deadlocks which takes care of some of the shortcomings of deadlock-prevention such as low device utilization and reduced system throughput. In this unit, you will therefore learn how some of the algorithms for deadlock prevention, deadlock avoidance and deadlock detection and recovery are implemented. 2.0 Objectives • At the end of this unit you should be able to: • Describe deadlock prevention • Explain what is meant by deadlock avoidance • Describe Banker’s algorithm • Describe Resource-Allocation graph algorithm • Explain what is meant by safe state • Describe Deadlock lock detection algorithms and how to recover from deadlock