Write an OS program to implement FCFS Disk Scheduling algorithm.

 

#include<stdio.h>

#include<math.h>

#include<stdlib.h>

int main()

{

    int queue[20],n,head,i,j,k,seek=0,max,diff;

    printf("\nEnter the max range of disk : ");

    scanf("%d",&max);

    printf("Enter the size of queue request : ");

    scanf("%d",&n);

    printf("Enter the queue of disk positions to be read : ");

    for (i=1;i<=n;i++)

        scanf("%d",&queue[i]);

    printf("Enter the initial head position : ");

    scanf("%d",&head);

    queue[0]=head;

    for (j=0;j<=n-1;j++)

    {

         diff = abs(queue[j+1]-queue[j]);

         seek+=diff;

         printf("\nDisk head moves from %d to %d with head movement of %d",queue[j],queue[j+1],diff);

    }

    printf("\n\nTotal Head Movement is %d\n",seek);

    return 0;

}

/**

ty56@pc16:~/ty56/ty_OS2_56/Assignment 3$ cc fcfs.c

ty56@pc16:~/ty56/ty_OS2_56/Assignment 3$ ./a.out

Enter the max range of disk : 200

Enter the size of queue request : 8

Enter the queue of disk positions to be read : 98

183

41

122

14

124

65

67

Enter the initial head position : 53

Disk head moves from 53 to 98 with head movement of 45

Disk head moves from 98 to 183 with head movement of 85

Disk head moves from 183 to 41 with head movement of 142

Disk head moves from 41 to 122 with head movement of 81

Disk head moves from 122 to 14 with head movement of 108

Disk head moves from 14 to 124 with head movement of 110

Disk head moves from 124 to 65 with head movement of 59

Disk head moves from 65 to 67 with head movement of 2

Total Head Movement is 632

**/