Banker's Algorithm and Deadlock Recovery


In the study of operating systems, the Banker's algorithm and deadlock recovery play vital roles in managing resources and avoiding deadlocks. Deadlocks are situations in which two or more processes are unable to proceed because each is waiting for a resource held by the other. The Banker's algorithm, on the other hand, is a resource allocation and deadlock avoidance algorithm that is widely used to ensure the safe execution of processes.

Deadlock Recovery

When a deadlock occurs, it is necessary to recover the system from this state to resume normal operation. Deadlock recovery strategies can be broadly categorized into three types:

  1. Prevention: In this strategy, the occurrence of deadlock is prevented by ensuring that at least one condition necessary for deadlock cannot hold. However, this approach can be quite restrictive as it requires additional information and control mechanisms.

  2. Avoidance: Unlike prevention, avoidance strategies allow the possibility of deadlock, but they employ algorithms to detect and avoid the allocation of resources that may lead to deadlock. One such algorithm is the Banker's algorithm, which we will discuss in detail later.

  3. Detection and Recovery: In cases where prevention and avoidance are not feasible, the system provides mechanisms for detecting deadlocks and recovering from them. This can be done through various techniques such as resource preemption and killing processes involved in the deadlock.

Banker's Algorithm

The Banker's algorithm is an algorithm used in operating systems to manage and allocate scarce resources among multiple processes. Its main objective is to avoid deadlocks by determining if a particular request from a process can be granted based on the available resources in the system. It ensures that the system will always be in a safe state, where all processes can complete their execution without entering a deadlock.

The Banker's algorithm employs the following general steps:

  1. Initialization: The algorithm starts by obtaining information about the maximum resource requirements of each process, as well as the total resources available in the system.

  2. Request Evaluation: When a process requests additional resources, the Banker's algorithm checks if granting those resources will result in a safe state or potential deadlock. It does so by simulating the allocation and checking if there is a valid sequence of resource allocations that can allow all processes to complete.

  3. Resource Allocation: If granting the resources does not lead to a deadlock, the Banker's algorithm allocates the resources to the requesting process. Otherwise, the process is forced to wait until the requested resources become available.


The Banker's algorithm and deadlock recovery strategies are crucial in managing resources and preventing deadlocks in operating systems. With the Banker's algorithm, it becomes possible to allocate resources in a manner that ensures the system's safety, avoiding potential deadlocks. In cases where deadlocks cannot be prevented or avoided, proper detection and recovery mechanisms help in restoring normal operation and minimizing disruptions.

Understanding and implementing these concepts is essential for any operating system course, as it provides the foundation for effective resource management and maintaining system stability. By employing these techniques, system administrators and developers can ensure smoother execution and improved efficiency of processes.

noob to master © copyleft