Programming Assignment HW4: CPU Scheduling v03/17/19 6 PM Deadline March 28th, 2019, 8 PM. Late deadline with penalty March 29th, 2019, 8 PM

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1 CS 370: OPERATING SYSTEMS SPRING 2019 Department of Computer Science URL: Colorado State University INSTRUCTOR: Yashwant Malaiya Programming Assignment HW4: CPU Scheduling v03/17/19 6 PM Deadline March 28th, 2019, 8 PM. Late deadline with penalty March 29th, 2019, 8 PM Purpose: The objective of this assignment is to become familiar with some of the basic CPU scheduling algorithms. You will be implementing three scheduling algorithms while generating the Gantt charts and tracking measures of effectiveness. Description of assignment: In this assignment, you will be implementing basic CPU scheduling algorithms specified below. The first command line argument specifies the file name which contains the list of processes for your scheduling algorithms. The next command line argument specifies the time quantum (for round-robin). Implement the following three CPU scheduling algorithms using either C or Python programming language. Assume that all jobs are CPU bound (i.e., they do not block for I/O), and the context-switching time is negligible. Also assume that in Round Robin if a new process arrives the same instant when a process is switched out, the new process gets in the ready queue first. First Come First Serve (FCFS) Shortest Job First (SJF) (non-preemptive). Round Robin (RR) with the specified quantum. You must produce a Gantt chart for each scheduling algorithm to help visualize the sequence of execution for each process (See example output below). You will analyze the performance of these scheduling algorithms by tracking the turnaround time and waiting time for each process and printing the average waiting time, average turnaround time and throughput after all processes have completed. The turnaround time for a process is the difference between a job s submission and completion times. The average turnaround time reports the average for the set of processes that were scheduled. The waiting time for a process reflects the total amount of time spent by that process in the ready queue. The average waiting time reports the average for the set of processes that were scheduled.

2 The throughput for a scheduling algorithm measures the total number of tasks processes per unit time. Requirements of Task 1. Your program must accept two arguments from the command line. The first argument is the name of the file containing the processes (for example: processes.csv). This file is comma-separated with three columns (process ID, arrival time and burst time) with each row for an individual process. You can assume that this file will have a maximum of 10 processes. The second argument is the time quantum for Round Robin scheduling. 2. Your program (scheduler.c or scheduler.py) should be able to perform FCFS, SJF (nonpreemptive), and Round Robin scheduling correctly given a set of processes and arrival time and burst time for each process. 3. Implement FCFS and print a Gantt chart showing the execution sequence using the format shown below (align the number in the columns). Report waiting time and turnaround time for each process. Also, report the average values for waiting time and turnaround time, and the overall throughput for all the processes. 4. Repeat item 3 above for SJF. 5. Repeat item 3 above for RR using the specified quantum. Note: The processes in the file (first command line argument file) may be specified in such a way that it may result in some IDLE time when there are no processes ready to be executed. During the IDLE time the CPU has no processes to execute and waits for the next process to appear in the ready queue. Your Gantt chart should include these IDLE times.

3 Example: Input: processes.csv ProcessID,Arrival Time,Burst Time 0,1,3 1,0,5 2,9,8 3,10,6 Note: The first line in the processes.csv file has headers Process ID, Arrival Time, Burst Time. Example Output: machine:<path-name>$ python scheduler.py processes.txt 4 ###################### FCFS ###################### Process 1: Waiting time: 0, Turnaround time: 5 Process 0: Waiting time: 4, Turnaround time: 7 Process 2: Waiting time: 0, Turnaround time: 8 Process 3: Waiting time: 7, Turnaround time: 13 Gantt Chart: Process 1: 0 5 Process 0: 5 8 Process IDLE: 8 9 Process 2: 9 17 Process 3: Average waiting time: 2.75 Average turnaround time: 8.25 Throughput: ##################### SJFS ######################## Process 1: Waiting time: 0, Turnaround time: 5 Process 0: Waiting time: 4, Turnaround time: 7 Process 2: Waiting time: 0, Turnaround time: 8 Process 3: Waiting time: 7, Turnaround time: 13

4 Gantt Chart: Process 1: 0 5 Process 0: 5 8 Process IDLE: 8 9 Process 2: 9 17 Process 3: Average waiting time: 2.75 Average turnaround time: 8.25 Throughput: ##################### Round Robin Scheduler ######################## Time Quantum: 4 Process 1: Waiting time: 3, Turnaround time: 8 Process 0: Waiting time: 3, Turnaround time: 6 Process 2: Waiting time: 4, Turnaround time: 12 Process 3: Waiting time: 7, Turnaround time: 13 Gantt Chart: Process 1: 0 4 Process 0: 4 7 Process 1: 7 8 Process IDLE: 8 9 Process 2: 9 13 Process 3: Process 2: Process 3: Average waiting time: 4.25 Average turnaround time: 9.75 Throughput: Note: While printing the Gantt Chart align the start and end times in a readable format. The format for command line arguments for grading will be: >./scheduler <filename> <time quantum> (or)

5 > python scheduler.py <filename> <time quantum> The filename is the name of the file containing the information about all the processes. What to Submit? Submit a single.zip or.tar file using Canvas. The.zip or.tar file should contain the following: All.c or.py files related to the assignment (please document your code). A README.txt file containing a description of each file and any information you feel the grader needs to grade your program. The grader by default compiles the scheduler.c or runs scheduler.py. If you code your program in multiple files you will need to specify the executable file which runs all the three scheduling algorithms. Include a makefile if you use C. You submitted files should not include any directory structure. Your code must be executable on the machines in the 120 lab. Filename Convention: By default, the grader will execute the executable named scheduler (compiled from C code) or scheduler.py. You can name other.c or.py files anything you want. If your filename is other than the default, you will have to mention this executable file name in your README.txt. Your archive file should be named as <LastName>_<FirstName>_HW4.<tar/zip>. E.g. if you are John Doe and submitting for HW4, then the zip file should be named Doe_John_HW4.zip. Grading: This assignment is worth 100 points. Points are allocated in the following way: 20pts correctly implementing FCFS scheduling algorithm 12.5pts producing the correct Gantt chart 2.5pts getting throughput 2.5pts Individual waiting time (2pts) + Average Waiting Time (0.5pts) 2.5pts Individual Turnaround Time (2pts) + Average Turnaround time (0.5pts) 30pts correctly implementing SJF [non-preemptive] scheduling algorithm 22.5pts producing the correct Gantt chart. 2.5pts getting throughput 2.5pts Individual waiting time (2pts) + Average Waiting Time (0.5pts) 2.5pts Individual Turnaround Time (2pts) + Average Turnaround time (0.5pts) 40pts correctly implementing RR scheduling algorithm

6 32.5pts producing the correct Gantt chart 2.5pts getting throughput 2.5pts Individual waiting time (2pts) + Average Waiting Time (0.5pts) 2.5pts Individual Turnaround Time (2pts) + Average Turnaround time (0.5pts) 5pts Answering the questions provided below. 3pts Suitable documentation of code in the code files and README file. 2pts compilation without warnings or errors. Questions: (Include answers in the README.txt file) 1 point each: 1. What is the other name for Shortest Job First Preemptive Algorithm? 2. What are the 5 different states a process can be in scheduling (Look into process state diagram)? 3. Shortest Job First is like Priority Scheduling with the priority based on of the process? 4. effect is the primary disadvantage of First Come First Serve Scheduling algorithm. 5. How does Multi Level Feedback queue prevent starvation of processes that waits too long in lower priority queue? Note: You are required to work alone on this assignment. You may not use any code not written by yourself personally. Late Policy Click here for the class policy on submitting late assignments. Revisions: 3/16/2019, 3/17/2019: The contents of processes.csv and the output results updated..