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Experiment No - 7 A. Write A Program To Demonstrate The Concept of Deadlock Avoidance Through Banker's Algorithm

The document presents a program that implements the Banker's Algorithm to demonstrate deadlock avoidance in resource allocation among processes. It defines the number of processes and resources, their maximum demands, and current allocations, and includes functions to check for safe states and handle resource requests. The output indicates whether a resource request is granted or denied, along with the safe sequence of process execution.

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16 views3 pages

Experiment No - 7 A. Write A Program To Demonstrate The Concept of Deadlock Avoidance Through Banker's Algorithm

The document presents a program that implements the Banker's Algorithm to demonstrate deadlock avoidance in resource allocation among processes. It defines the number of processes and resources, their maximum demands, and current allocations, and includes functions to check for safe states and handle resource requests. The output indicates whether a resource request is granted or denied, along with the safe sequence of process execution.

Uploaded by

birwadkarmadhura
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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EXPERIMENT NO – 7

a. Write a program to demonstrate the concept of deadlock avoidance through


Banker’s Algorithm

#include <stdio.h>
#include <stdbool.h>

#define P 5 // Number of processes


#define R 3 // Number of resources

int available[R] = {3, 3, 2}; // Available resources


int max_demand[P][R] = {
​ {7, 5, 3},
​ {3, 2, 2},
​ {9, 0, 2},
​ {2, 2, 2},
​ {4, 3, 3}
};
int allocation[P][R] = {
​ {0, 1, 0},
​ {2, 0, 0},
​ {3, 0, 2},
​ {2, 1, 1},
​ {0, 0, 2}
};

bool is_safe_state(int work[], int finish[], int safe_sequence[]) {


​ int count = 0;
​ bool allocated;

​ for (int i = 0; i < P; i++)


​ finish[i] = 0;

​ while (count < P) {


​ allocated = false;
​ for (int i = 0; i < P; i++) {
​ bool can_allocate = true;
​ for (int j = 0; j < R; j++) {
​ if (max_demand[i][j] - allocation[i][j] > work[j]) {
​ can_allocate = false;
​ break;
​ }
​ }
​ if (!finish[i] && can_allocate) {
​ for (int j = 0; j < R; j++)
​ work[j] += allocation[i][j];
​ safe_sequence[count++] = i;
​ finish[i] = 1;
​ allocated = true;
​ }
​ }
​ if (!allocated)
​ return false;
​ }
​ return true;
}

bool request_resources(int process_id, int request[]) {


​ for (int i = 0; i < R; i++) {
​ if (request[i] > max_demand[process_id][i] - allocation[process_id][i]) {
​ printf("Process %d has exceeded its maximum claim!\n", process_id);
​ return false;
​ }
​ if (request[i] > available[i]) {
​ printf("Resources not available for process %d request!\n", process_id);
​ return false;
​ }
​ }

​ for (int i = 0; i < R; i++) {


​ available[i] -= request[i];
​ allocation[process_id][i] += request[i];
​ }

​ int work[R], finish[P], safe_sequence[P];


​ for (int i = 0; i < R; i++)
​ work[i] = available[i];

​ if (is_safe_state(work, finish, safe_sequence)) {


​ printf("Request granted. Safe sequence: ");
​ for (int i = 0; i < P; i++)
​ printf("%d ", safe_sequence[i]);
​ printf("\n");
​ return true;
​ } else {
​ printf("Request denied. Would lead to an unsafe state.\n");
​ for (int i = 0; i < R; i++) {
​ available[i] += request[i];
​ allocation[process_id][i] -= request[i];
​ }
​ return false;
​ }
}

int main() {
​ int request[R] = {1, 0, 2};
​ int process_id = 1;
​ request_resources(process_id, request);
​ return 0;
}

OUTPUT:

Request granted.
Safe sequence: 1 3 4 0 2

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