Question

Question I

This question carries 20% of the marks for this assignment.

You are asked to develop a set of bash shell script:

1. Write a script that asks for the user's salary per month. If it is less or equals to 800, print a message saying that you need to get another job to increase your income, what you earn is the Minim living cost. If the user's salary is higher than 800 and below 2000, print a message telling the user that your income is just right to cover your expenses. [10 marks]
2. Write a script that takes exactly one argument, a file name. If the number of arguments is more or less than one, print a usage message. If the argument is not a file name, print another message. For the given file, print on the screen its content. [5 marks]
3. Write a script that does the following [5 marks]

• Display the name of the script being executed.
• Display the second, third and fifth argument given to the script.
• Display the total number of arguments passed to the script.
• Print all the values of the remaining arguments.
• Print the number of arguments

Question II

This question carries 50% of the marks for this assignment.

This question is about avoiding race condition by using synchronization mechanism provided by the JAVA programming language. We provided you with a Netbeans JAVA project. The project idea is as follows: we want to merge the content of four files into a single file, as follows. Below is the content of all four files:

F1 content: 1 1 1 1

F2 content: 2 2 2 2

F3 content: 3 3 3 3

F4 content: 4 4 4 4

After merging them into the Sink file, we expect the following content in the sink file:1234123412341234

We want to read from each file only one integer value at a time (starting form file number 1, number 2 and so on) and write theses integers values ( in the same order we read them) into a specific sink file, we want to repeat it until all file files are empty.

Please note that all files have the same number of integers.

We have provided you with a template project that needs to be modified to accomplish the above task correctly.

The project is composed of the following classes including four text files:

Four text files called “f1.txt”, “f2.txt”, “f3.txt” and “f4.txt”, each file has a sequence of integer corresponding its name, for instance “f2.txt” contains a sequence of integers all are 2.

The following JAVA source code files are included in the NetBeans projects:

WriteToFile: A helper class to write into a file.

SyncWriteToFile: which control the access to the file, it does so by aggregating an object of the class “WriteToFile”

MergeFiles that extends Thread: it is intended to read all integers form a specific file and use an object of “SyncWriteToFile” to write them into the sink file at the appropriate place.

TMA_Tm298_SummerEgJo: contains the main method to test the program

Read the source code of the above classes carefully and run the project. You will discover that the content of the sink file is not as expected and each time you run it you got a different content. Provide screen shots form running the project without any modification. Provide convincing justification, why you got these results. [15 marks]

In order to get the expected sink file content, you need to modify the project as follows:

You can do so by first identifying the shared resources and then the critical section code in the project. [10 marks]. Then you need to change the critical section code so that the sink file contains the following result no matter how many times you run the project. The sink file correct content is :1234123412341234. [25 marks]

You are sked to submit the whole project (as one zip file) after all modification.

Question III

This question carries 30% of the marks for this assignment.

There are four processes P1, P2, P3 and P4 that will be executed by a scheduler on a concurrent system using different scheduling policy. Their arrival times and service times are shown in the following table. Complete the table using the listed three scheduling policy, draw the Gantt chart (assuming that the quantum time is 2 second for preemptive scheduling algorithm) and calculate the average waiting time [10 marks]:

1. When a FIFO scheduling policy is used.
2. When SJF (non-preemptive) scheduling policy is used.
3. When RR scheduling policy is used.

Process ID	Arrival time in second	Service time	Finish time	Turnaround	Waiting time	Normalized turnaround
P1	0	3	?	?	?	?
P2	1	5	?	?	?	?
P3	4	2	?	?	?	?
P4	2	4	?	?	?	?

ues this code

package tma_tm298_summer.egjo;

import java.io.FileNotFoundException;

/**
*
* @author macbook
*/
public class TMA_Tm298_SummerEgJo {

/**
* @param args the command line arguments
*/
public static void main(String[] args) throws FileNotFoundException, InterruptedException {
// TODO code application logic here
SyncWriteToFile outToFile= new SyncWriteToFile("sinkFile.txt");
MergeFiles file1= new MergeFiles(1, "f1.txt", outToFile);
MergeFiles file2= new MergeFiles(2, "f2.txt", outToFile);
MergeFiles file3= new MergeFiles(3, "f3.txt", outToFile);
MergeFiles file4= new MergeFiles(4, "f4.txt", outToFile);
System.out.println("file merging started");
file1.start();
file2.start();
file3.start();
file4.start();
// let main wait until all data merged
file4.join();
System.out.println("file merging ended succesfully");
}
  
}

Answer 1

question 1)

2)

3)