MULTIPLE SLEEPING BARBERS - MULTIPROCESSOR OPERATING SYSTEMS

AIM:

To write a java program for the multiple sleeping barbers in multi-processor operating system.

ALGORITHM:

Step 1:              Start the program

Step 2:              while the barber in process is true runs an infinite loop

Step 3:              Barber tries to acquire a customer.

Step 4:              If none is available the barber goes to sleep.

Step 5:              At this time, he has been awakened and wants to modify the number of available seats.

Step 6:              Barber waits for a customer to arrive

Step 7:              If customer arrived run an infinite loop.

Step 8:              Checks if the NumberOfFreeSeats is greater than zero, sit down on the chair. Otherwise goto step 13.

Step 9:              V(Customers) notify the barber, who's waiting that there is a customer

Step 10:          V(accessSeats) don't need to lock the chairs anymore

Step 11:          P(Barber) now it's this customers turn, but wait if the barber is busy

Step 12:          Here the customer is having his hair cut

Step 13:          V(accessSeats) The lock on the seats is removed. Customer leaves without a haircut.

Step 14:          End of program.

PROGRAM:

import java.io.*;

import java.lang.*;

class cust {

    public int disp(int cn)

    {

        return(cn);

    }

}

class em1 extends Thread{

    main2 m=new main2();

    cust c=new cust();

public synchronized void run()

{

    try

    {

    while(m.cnum<=m.n)

    {

        int t=c.disp(m.cnum++);

    System.out.println("Barber2 serves Customer "+t);

        Thread.sleep(2000);

    }

    System.out.println("Barber2 sleeps ");

  

   }

    catch(Exception e){}

}

   

}

public class main2 {

static int cnum=1,n,ch,n1;

 

    public static void  main(String[] args) {

        try

        {

         BufferedReader br=new BufferedReader(new InputStreamReader(System.in));  

         em1 e=new em1();

         cust c=new cust();             

         int j;

             System.out.println("Enter no of Chairs including two barber Chairs: ");

         ch=Integer.parseInt(br.readLine());

             System.out.println("Enter no of Customers : ");

         n=Integer.parseInt(br.readLine());

         e.start();

             if(ch<n)

         {

             n1=n-ch;

             System.out.println(n1+" Customers Leaved from the Shop");         

             n=n-n1;

             while(cnum<=n)

         {

         int t=c.disp(cnum++);

         System.out.println("Barber1 serves " +" Customer " + t);

         Thread.sleep(1000);

             }

             }

            else

             {

         while(cnum<=n)

         {

         int t=c.disp(cnum++);

         System.out.println("Barber1 serves " +" Customer " + t);

         Thread.sleep(1000);

         }

             }

             System.out.println("Barber1 sleeps ");

        

         }

        catch(Exception e){}

    }

}

OUTPUT:

U:\OS_Lab\EX123>javac main2.java

U:\OS_Lab\EX123>java main2

Enter no of Chairs including two barber Chairs:5

Enter no of Customers :4

Barber1 serves  Customer 1

Barber2 serves Customer 2

Barber1 serves  Customer 3

Barber2 sleeps

Barber1 serves  Customer 4

Barber1 sleeps

U:\OS_Lab\EX123>java main2

Enter no of Chairs including two barber Chairs:4

Enter no of Customers :4

Barber1 serves  Customer 1

Barber2 serves Customer 2

Barber1 serves  Customer 3

Barber2 sleeps

Barber1 serves  Customer 4

Barber1 sleeps

U:\OS_Lab\EX123>java main2

Enter no of Chairs including two barber Chairs:3

Enter no of Customers :4

1 Customers Leaved from the Shop

Barber2 serves Customer 1

Barber1 serves  Customer 2

Barber1 serves  Customer 3

Barber2 sleeps

Barber1 sleeps