Banker's Algorithm in Operating System - GeeksforGeeks (2024)

// C# Program for Bankers Algorithm

using System;

using System.Collections.Generic;

class GFG

{

static int n = 5; // Number of processes

static int m = 3; // Number of resources

int [,]need = new int[n, m];

int [,]max;

int [,]alloc;

int []avail;

int []safeSequence = new int[n];

void initializeValues()

{

// P0, P1, P2, P3, P4 are the Process

// names here Allocation Matrix

alloc = new int[,] {{ 0, 1, 0 }, //P0

{ 2, 0, 0 }, //P1

{ 3, 0, 2 }, //P2

{ 2, 1, 1 }, //P3

{ 0, 0, 2 }};//P4

// MAX Matrix

max = new int[,] {{ 7, 5, 3 }, //P0

{ 3, 2, 2 }, //P1

{ 9, 0, 2 }, //P2

{ 2, 2, 2 }, //P3

{ 4, 3, 3 }};//P4

// Available Resources

avail = new int[] { 3, 3, 2 };

}

void isSafe()

{

int count = 0;

// visited array to find the

// already allocated process

Boolean []visited = new Boolean[n];

for (int i = 0; i < n; i++)

{

visited[i] = false;

}

// work array to store the copy of

// available resources

int []work = new int[m];

for (int i = 0; i < m; i++)

{

work[i] = avail[i];

}

while (count<n)

{

Boolean flag = false;

for (int i = 0; i < n; i++)

{

if (visited[i] == false)

{

int j;

for (j = 0; j < m; j++)

{

if (need[i, j] > work[j])

break;

}

if (j == m)

{

safeSequence[count++] = i;

visited[i] = true;

flag = true;

for (j = 0; j < m; j++)

{

work[j] = work[j] + alloc[i, j];

}

}

}

}

if (flag == false)

{

break;

}

}

if (count < n)

{

Console.WriteLine("The System is UnSafe!");

}

else

{

//System.out.println("The given System is Safe");

Console.WriteLine("Following is the SAFE Sequence");

for (int i = 0; i < n; i++)

{

Console.Write("P" + safeSequence[i]);

if (i != n - 1)

Console.Write(" -> ");

}

}

}

void calculateNeed()

{

for (int i = 0;i < n; i++)

{

for (int j = 0;j < m; j++)

{

need[i, j] = max[i, j] - alloc[i, j];

}

}

}

// Driver Code

public static void Main(String[] args)

{

GFG gfg = new GFG();

gfg.initializeValues();

// Calculate the Need Matrix

gfg.calculateNeed();

// Check whether system is in

// safe state or not

gfg.isSafe();

}

}

// This code is contributed by Rajput-Ji

Banker's Algorithm in Operating System - GeeksforGeeks (2024)

FAQs

What is Banker's algorithm in OS? ›

Banker's algorithm is a resource allocation and deadlock avoidance algorithm developed by Edsger Dijkstra that tests for safety by simulating the allocation of predetermined maximum possible amounts of all resources, and then makes an "s-state" check to test for possible deadlock conditions for all other pending ...

How to calculate available in banker's algorithm? ›

Suppose n is the number of processes, and m is the number of each type of resource used in a computer system. Available: It is an array of length 'm' that defines each type of resource available in the system. When Available[j] = K, means that 'K' instances of Resources type R[j] are available in the system.

What is banker's algorithm in GFG? ›

The banker's algorithm is a resource allocation and deadlock avoidance algorithm that tests for safety by simulating the allocation for the predetermined maximum possible amounts of all resources, then makes an “s-state” check to test for possible activities, before deciding whether allocation should be allowed to ...

What is the time complexity of the bankers algorithm? ›

The time complexity of the Banker's algorithm as a function of the number n of processes and m of resources is o(n*n*m).

How to avoid deadlock in OS? ›

Deadlock can be prevented by eliminating any of the four necessary conditions, which are mutual exclusion, hold and wait, no preemption, and circular wait.

How to recover from deadlock in OS? ›

If a deadlock occurs, the operating system needs to recover from it by breaking the cycle of waiting processes. There are two main strategies for doing this: process termination and resource preemption.

What is the weakness of the banker's algorithm? ›

Disadvantages of the Banker's Algorithm

It requires the number of processes to be fixed; no additional processes can start while it is executing. It requires that the number of resources remain fixed; no resource may go down for any reason without the possibility of deadlock occurring.

How to detect deadlock? ›

The most common way to detect and recover from deadlocks is through detection algorithms. There are several types of detection algorithms, including Wait-For Graphs, Banker's Algorithm, Resource Allocation Graphs, Combined Detection Algorithms, and Timeouts.

How to find safe sequence in OS? ›

A safe sequence in OS is sequence of processes <P1 , P2, ..., Pn> for the current allocation state if, for each Pi , the resource requests that Pi make can be satisfied by the currently available resources plus the resources held by all Pj, with j < i( I.e. if all the processes prior to Pi finish and free up their ...

What is deadlock in OS? ›

Deadlock in OS refers to a situation where more than one or two processes or threads are not able to proceed because each is waiting for the other to release a resource. In other words, it's a state where a group of processes become stuck in a way that they can't make any progress.

What is Bankers Algorithm in OS coding ninjas? ›

Banker's algorithm ensures that the processes are allocated the resources without getting into any unsafe state. Banker's algorithm cannot be practically implemented as it is not feasible to determine the number of resources a process may need beforehand. Happy Learning, Ninjas!

What is the bankers algorithm theory in OS? ›

The Bankers Algorithm in OS is a deadlock avoidance algorithm used to avoid deadlocks and to ensure safe execution of processes. The algorithm maintains a matrix of maximum and allocated resources for each process and checks if the system is in a safe state before allowing a process to request additional resources.

What is starvation in OS? ›

Starvation in operating system occurs when a process waits for an indefinite time to get the resource it requires. Deadlock is a process design/distributed design issue. Starvation is a scheduler issue. Deadlock is also known as circular waiting. Another name for starvation is lived lock.

What is the safe state in OS? ›

A state is safe if the system can allocate resources to the various processes in some particular order and avoid deadlock in doing so. An unsafe state is a state that may lead to deadlock. Not all unsafe states are actual deadlock. Our goal in avoiding deadlock is to avoid the unsafe states.

What is the scheduling algorithm in OS? ›

One of the main tasks of an operating system is to manage the execution of multiple processes that share the same CPU and other resources. To do this, the operating system uses scheduling algorithms that determine which process gets to run on the CPU, for how long, and in what order.

What is a deadlock in OS? ›

Deadlock in OS refers to a situation where more than one or two processes or threads are not able to proceed because each is waiting for the other to release a resource. In other words, it's a state where a group of processes become stuck in a way that they can't make any progress.

What is algorithm in banking? ›

Simply put, algorithmic banking is the use of complex mathematical algorithms to drive better business decision making.

What is safe sequence in OS with an example? ›

A safe sequence in OS is sequence of processes <P1 , P2, ..., Pn> for the current allocation state if, for each Pi , the resource requests that Pi make can be satisfied by the currently available resources plus the resources held by all Pj, with j < i( I.e. if all the processes prior to Pi finish and free up their ...

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