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Zheng Wang
ID: 5826905
SIMULATOR FOR CPU SCHEDULING
FCFS SCHEDULING
FCFS means First- Come, First-Served Scheduling, the CPU will be allocated to the
process come first, the second process have to wait until the first process complete.
FCFS SCHEDULING
Example
PREEMPTIVE SJF SCHEDULING
Preemptive SJF is called shortest-remaining-time-first (SRTF) algorithm, the CPU will
always be allocated to the process that has the shortest remaining burst time in the
current ready queue. The process which is currently in execution, runs until it complete
or a new process is added in the cpu Scheduler that requires smaller amount of time
for execution.
Continue
PREEMPTIVE SJF SCHEDULING
The following omitted
PREEMPTIVE SJF SCHEDULING
Example
PRIORITY SCHEDULING
In priority scheduling, The CPU is allocated to the process with the highest priority,
equal-priority processes are scheduled in FCFS order.
PRIORITY SCHEDULING
Example
ROUND ROBIN SCHEDULING
In Round Robin scheduling, each process gets a small unit of CPU time (time
quantum). After this time has elapsed, the process is preempted and added to the end
of the ready queue.
ROUND ROBIN SCHEDULING
Example
Code
package project1;
import java.util.ArrayList;
import java.util.Scanner;
public class Simulator {
static Scanner s = new Scanner(System.in);
static ArrayList<Process> Processes = new ArrayList<Process>();
public static void main(String[] args) {
String S;
do{
System.out.println("MENU: \n1 - create a new process\n2 - display
processes"
+ "\n3 - restart(delete all processes created)\n4 - perform
FCFS Scheduling"
+ "\n5 - perform Preemptive SJF Scheduling(SRTF)\n6 -
preform Priority Scheduling"
+ "\n7 - perform Round Robin Scheduling\n8 - exit");
System.out.print("SELECT: ");
S = s.next();
if(S.equals("1")){
createAProcess();
}else if(S.equals("2")){
displayList();
}else if(S.equals("3")){
Processes.clear();
}else if(S.equals("4")){
FCFS();
}else if(S.equals("5")){
PreemptiveSJF();
}else if(S.equals("6")){
Priority();
}else if(S.equals("7")){
RoundRobin();
}else if(S.equals("8")){
break;
}else{
System.out.println("WRONG INPUT!");
}
}while(!S.equals("8"));
}
public static void createAProcess(){
System.out.println("Please enter ");
System.out.print("Process Name: ");
String processN = s.next();
System.out.print("Burst Time: ");
int burstT = s.nextInt();
Processes.add(new Process(processN, burstT));
System.out.print("Creation successed. Countiue creating?(y -
countinue/any other - return to menu): ");
String S = s.next();
if(S.equalsIgnoreCase("y")){
createAProcess();
}else{
package project1;
public class Process {
private String processN;
private int burstT;
private int arrivalT;
private int priority;
private int finishedBT;
public Process(String processN, int burstT){
this.setProcessN(processN);
this.setBurstT(burstT);
}
public String getProcessN() {
return processN;
}
public void setProcessN(String processN) {
this.processN = processN;
}
public int getBurstT() {
return burstT;
}
public void setBurstT(int burstT) {
this.burstT = burstT;
}
public int getArrivalT() {
return arrivalT;
}
public void setArrivalT(int arrivalT) {
this.arrivalT = arrivalT;
}
public int getPriority() {
return priority;
}
public void setPriority(int priority) {
this.priority = priority;
}
@Override
public String toString(){
return String.format("%-10s %-11d %-15d %-10d", this.processN,
this.burstT, this.arrivalT, this.priority);
}
public int getFinishedBT() {
return finishedBT;
}
public void setFinishedBT(int finishedBT) {
