Page replacement (FIFO)

    

              Page replacement (FIFO)

#include<stdio.h>

int main()

{

int i,j,n,a[50],frame[10],no,k,avail,count=0;

            printf("\n ENTER THE NUMBER OF PAGES:\n");

scanf("%d",&n);

            printf("\n ENTER THE PAGE NUMBER :\n");

            for(i=1;i<=n;i++)

            scanf("%d",&a[i]);

            printf("\n ENTER THE NUMBER OF FRAMES :");

            scanf("%d",&no);

for(i=0;i<no;i++)

            frame[i]= -1;

                        j=0;

                        printf("\tref string\t page frames\n");

for(i=1;i<=n;i++)

                        {

                                    printf("%d\t\t",a[i]);

                                    avail=0;

                                    for(k=0;k<no;k++)

if(frame[k]==a[i])

                                                avail=1;

                                    if (avail==0)

                                    {

                                                frame[j]=a[i];

                                                j=(j+1)%no;

                                                count++;

                                                for(k=0;k<no;k++)

                                                printf("%d\t",frame[k]);

}

                                    printf("\n");

}

                        printf("Page Fault Is %d",count);

                        return 0;

}

OUTPUT:

ENTER THE NUMBER OF PAGES:  20

ENTER THE PAGE NUMBER :       7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1

ENTER THE NUMBER OF FRAMES :3

      ref string       page frames

7               7       -1      -1

0               7       0       -1

1               7       0       1

2               2       0       1

0

3               2       3       1

0               2       3       0

4               4       3       0

2               4       2       0

3               4       2       3

0               0       2       3

3

2

1               0       1       3

2               0       1       2

0

1

7               7       1       2

0               7       0       2

1               7       0       1

Page Fault Is 15

Deadlock Detection Algorithm Implementation In C

Deadlock Detection Algorithm   Implementation In C

 
#include <stdio.h>
#include <conio.h>   
int main()
{
    int alloc[10][10],req[10][10],ins[10],avail[10],tp,tr,i,j;
    int tmp[10]={0},count=0;
    bool finish[10]={false},flag;
    printf("Enter total no of processes:");
    scanf("%d",&tp);
    printf("Enter total no of resources:");
    scanf("%d",&tr);
    printf("Randomly Generated Allocation Matrix:\n");     //itz tp x tr order matrix
    for(i=0;i
    {
        for(j=0;j
        {
            alloc[i][j]=rand()%5;
            printf("\t%d",alloc[i][j]);
        }
        printf("\n");
    }
    printf("Randomly Generated Request Matrix:\n");
    for(i=0;i
    {
        for(j=0;j
        {
            req[i][j]=rand()%5;
            printf("\t%d",req[i][j]);
        }
        printf("\n");
    }
    printf("Randomly Generated Resource Instance Vetctor:\n");
    for(i=0;i
    {
        ins[i]=rand()%10+tr+tp;       //Just to increase resource instances
        printf("\t%d",ins[i]);
    }

    //To calculate resource availability vector

    for(i=0;i
    {
        for(j=0;j
        {
            tmp[i]+=alloc[j][i];     //sum calculated columnwise for allocation matrix
        }
    }
    printf("\nCalculated Availability Vector:\n");
    for(i=0;i
    {
        avail[i]=ins[i]-tmp[i];
        printf("\t%d",avail[i]);
    }
    //main logic starts:P
    while(count
    {                              //if finish array has all true's(all processes to running state)
                                   //deadlock not detected and loop stops!
    for(i=0;i
    {
        count=0;
        //To check whether resources can be allocated any to blocked process 
        if(finish[i]==false)
        {
            for(j=0;j
            {
                    if(req[i][j]<=avail[j])
                    {
                        count++;
                    }
            }
            flag=false;
            if(count==tr)
            {
                for(j=0;j
                {
                    avail[j]+=alloc[i][j];        //allocated reources are released and added to available!
                }
                finish[i]=true;
                printf("\nProcess %d is transferred to running state and assumed finished",i+1);
            }
            else
                flag=true;
        }
    }
    count=0;
    for(j=0;j
    {
        if(finish[j]==true)
        {
            count++;
        }
    }
    }
    for(i=0;i
    {
        if(finish[i]==false)
        {
            printf("\n Oops! Deadlock detected and causing process is:process(%d)\n",i+1);
            break;
        }
    }
    i=i-1;
    if(finish[i]==true)
    printf("\nHurray! Deadlock not detected:-)\n");
    return 0;
}
/*
Sample Output:
Enter total no of processes:7
Enter total no of resources:3
Randomly Generated Allocation Matrix:
    3    1    2
    0    3    0
    1    2    4
    1    2    2
    0    4    3
    1    0    1
    2    1    1
Randomly Generated Request Matrix:
    3    2    4
    2    0    2
    3    2    0
    4    2    2
    3    4    2
    3    1    1
    2    4    3
Randomly Generated Resource Instance Vetctor:
    11    19    14
Calculated Availability Vector:
    3    6    1
Process 3 is transferred to running state and assumed finished
Process 4 is transferred to running state and assumed finished
Process 5 is transferred to running state and assumed finished
Process 6 is transferred to running state and assumed finished
Process 7 is transferred to running state and assumed finished
Process 1 is transferred to running state and assumed finished
Process 2 is transferred to running state and assumed finished
Hurray! Deadlock not detected:-)*/