# Which Data Structure Is Used in Banker’s Algorithm?

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Heather Bennett

The Banker’s algorithm is a resource allocation and deadlock avoidance algorithm used in operating systems. It ensures that the system can allocate resources to processes in a safe manner, preventing deadlocks from occurring. To understand which data structure is used in the Banker’s algorithm, let’s dive into the details.

## Resource Allocation and Deadlock Avoidance

Before we discuss the data structure used in the Banker’s algorithm, let’s briefly understand resource allocation and deadlock avoidance.

Resource Allocation:

Resource allocation refers to the process of assigning resources to processes in a computer system. These resources can be anything from memory to CPU time or I/O devices. The goal of resource allocation is to ensure efficient utilization of resources while satisfying the requirements of each process.

A deadlock occurs when two or more processes are unable to proceed because each is waiting for a resource held by another process. Deadlocks can lead to system instability and affect overall performance. Deadlock avoidance aims to prevent deadlocks from happening by carefully managing resource allocation.

## Data Structure Used in Banker’s Algorithm

The Banker’s algorithm utilizes several data structures to manage resource allocation and avoid deadlocks. The primary data structure used is called the resource-allocation graph. This graph represents the current state of resource allocation in the system.

### Resource-Allocation Graph

• The resource-allocation graph consists of two types of nodes: process nodes and resource nodes.
• Process nodes represent individual processes in the system, while resource nodes represent different types of resources available.
• The graph contains edges that represent the allocation and request relationships between processes and resources.

Let’s understand the different elements within the resource-allocation graph:

• Process Nodes:
• Each process node represents a process in the system.
• It contains information about the resources allocated to that process and the resources it still needs to complete its execution.

• Resource Nodes:
• Each resource node represents a type of resource available in the system.
• It contains information about the total number of instances of that resource and the number of instances currently allocated or available.

• Edges:
• The edges in the graph represent allocation and request relationships between processes and resources.
• An edge from a process node to a resource node signifies that the process is currently allocated an instance of that resource.
• An edge from a resource node to a process node indicates that the process has requested an additional instance of that resource.

In addition to the resource-allocation graph, other data structures are used to implement the Banker’s algorithm:

• Available Resource Vector:
• The available resource vector keeps track of the number of available instances of each type of resource at any given time. It helps determine whether a particular request can be granted without leading to a deadlock.

• Max Demand Matrix:
• The max demand matrix represents the maximum number of instances of each resource that a process may request. It provides a way to compare the current allocation and future requests with the maximum allowed for each process.

• Allocation Matrix:
• The allocation matrix keeps track of the resources currently allocated to each process. It provides information about the resources in use and helps determine if a request can be granted without exceeding the maximum limits.

By utilizing these data structures, the Banker’s algorithm can safely allocate resources to processes while avoiding deadlocks. The resource-allocation graph allows for a visual representation of the system state, while additional data structures provide necessary information for decision-making.

## Conclusion

The Banker’s algorithm is an essential tool in operating systems for resource allocation and deadlock avoidance. By utilizing data structures such as the resource-allocation graph, available resource vector, max demand matrix, and allocation matrix, it ensures that resources are allocated in a safe manner without causing deadlocks. Understanding these data structures is crucial for implementing and comprehending how the Banker’s algorithm works effectively.