Question

IN JAVA

Implement SRT scheduling algorithms based on following actions:

The simulation maintains the current time, t, which is initialized to 0 and is incremented after each simulation step. Each simulation step then consists of the following actions:

repeat until Rᵢ == 0 for all n processes /* repeat until all processes have terminated */
while no process is active, increment t /* if no process is ready to run, just advance t */
choose active processes pᵢ to run next
according to scheduling algorithm /* Ex: FIFO, SJF, SRT */
decrement Rᵢ /* pᵢ has accumulated 1 CPU time unit */
if Rᵢ == 0 /* process i has terminated */
set active flag of pᵢ = 0 /* process i is excluded from further consideration */
TTᵢ = t - Aᵢ /* the turnaround time of process i is the time
since arrival, TTᵢ, until the current time t */
compute the average turnaround time,
ATT, by averaging all values TTᵢ

Answer 1

import java.io.PrintWriter;
import java.io.OutputStreamWriter;
import java.io.IOException;

public class SRTF {
private static class Process {
private final int PID;
private final int submitTime;
private int burst;
private int completeTime;
private boolean dispatched;
  
public Process(int PID, int submitTime, int burst) {
this.PID = PID;
this.submitTime = submitTime;
this.burst = burst;
this.completeTime = -1;
this.dispatched = false;
}
  
public int getPID() {
return this.PID;
}
  
public int getSubmissionTime() {
return this.submitTime;
}
  
public int getBurst() {
return this.burst;
}
  
public void reduceBurst(int q) {
burst -= (int) Math.min(burst, q);
}
  
public void setCompleteTime(int time) {
this.completeTime = time;
}
  
public int getCompleteTime() {
return this.completeTime;
}
  
public boolean isCompleted() {
return this.completeTime != -1;
}
  
public void setDispatched() {
this.dispatched = true;
}
  
public boolean isDispatched() {
return this.dispatched;
}
}
  
private static boolean checkCompleted(Process[] parr) {
for(Process p : parr) {
if(!p.isCompleted()) {
return false;
}
}
return true;
}
  
public static void main(String[] args) throws IOException {
OutputStreamWriter osw = new OutputStreamWriter(System.out);
PrintWriter out = new PrintWriter(osw);
  
Process[] parr = new Process[5];
parr[0] = new Process(0, 1, 3);
parr[1] = new Process(1, 2, 1);
parr[2] = new Process(2, 2, 5);
parr[3] = new Process(3, 3, 4);
parr[4] = new Process(4, 4, 2);
  
int clock = 1;
int quantum = 1;
  
while(!checkCompleted(parr)) {
// Detect shortest burst process which
// has not completed
Process minBurstProc = null;
int minBurst = Integer.MAX_VALUE;
  
for(Process p : parr) {
if(!p.isCompleted() && p.getSubmissionTime() <= clock && p.getBurst() < minBurst) {
minBurst = p.getBurst();
minBurstProc = p;
}
}
  
clock += quantum;
  
if(minBurstProc != null) {
minBurstProc.reduceBurst(quantum);
  
if(minBurstProc.getBurst() == 0) {
minBurstProc.setCompleteTime(clock);
}
}
}
  
out.println("PID\tCompletion Time");
  
for(Process p : parr) {
out.print(p.getPID());
out.print("\t");
out.print(p.getCompleteTime());
out.println(" units");
}
  
out.close();
}
}