Question

Operating Siytem Concepts Homework No. 1 Variant No. 1 Student Cristian Anchei Paraschine (academic group, name, surname) I got the task.... (date, signature) Homework Submission Date: November 6th, 2019 Assignment: Consider the following set of processes, with the length of the CPU burst time given in milliseconds!: Process CPU burst time, ms Arrival time, ms Priority P 2 2 2 7 Ps 3 3 Draw a Gantt chart that illustrates process scheduling for these algorithms: a) First Come - First Served (FCFS); b) The Shortest Job - First (SJF), non-preemptive scheme; c) The Shortest Job - First (SJF), preemptive scheme; d) Round-robin (RR), when time quantum is equal to 3 ms. Calculate the average waiting, turnaround and response time of processes. Report Requirements a. The report is written by hand on sheets of A4 paper. b. The report should include: 4 (four) Gantt charts and corresponding calculations of the average values of the waiting time, the turnaround time, and the response time of the processes. c. Report Content: I. Signed assignment sheet II. Gantt charts and calculations Information is presented in abundance in the table.

Answer 1

FCFS - First Come First Served

Time-> 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 - P1 P4 I P5

Waiting time: Waiting time = (execution starting time) - (arrival time OR last execution end time) Waiting time of P1 = 0 - 0 = 0 Waiting time of P2 =2-1=1 Waiting time of P3 = 8 - 2 = 6 Waiting time of P4 = 10 - 3 = 7 Waiting time of P5 = 17-4 = 13| Total waiting time = 0+1+6+7+13 = 27 Average waiting time = 27/ 5 = 5.4 Turnaround time: Turnaround time = (execution completion time) - (arrival time) Turnaround time of P1 = 2-0 =2 Turnaround time of P2 = 8 - 1 = 7 Turnaround time of P3 = 10 -2 = 8 Turnaround time of P4 = 17-3 = 14 Turnaround time of P5 = 20 - 4 = 16 Total turnaround time = 2 + 7 + 8 + 14 + 16 = 47 Average turnaround time = 47 / 5 = 9.4

Response time: Response time = (first execution start time) - (arrival time) Response time of P1 = 0 - 0 = 0 Response time of P2 =2-1=1 Response time of P3 = 8 - 2 = 6 Response time of P4 = 10 - 3 = 7 Response time of P5 = 17 -4 = 13 Total response time = 0 +1 +6+ 7+ 13 = 27 Average response time = 27 / 5 = 5.4

SJFS - NPE - Shortest Job First Non Preemptive

Time-> 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 P1 P5 P2

Waiting time: Waiting time = (execution starting time) - (arrival time OR last execution end time) Waiting time of P1 = 0 - 0 = 0 Waiting time of P2 = 7 - 1 = 6 Waiting time of P3 = 2 - 2 = 0 Waiting time of P4 = 13 - 3 = 10 Waiting time of P5 = 4-4 = 0 Total waiting time = 0 + 6 +0+10 + 0 = 16 Average waiting time = 16/5 = 3.2 Turnaround time: Turnaround time = (execution completion time) - (arrival time) Turnaround time of P1 = 2 - 0= 2 Turnaround time of P2 = 13 - 1 = 12 Turnaround time of P3 - 4 - 2 = 2 Turnaround time of P4 = 20 - 3 = 17 Turnaround time of P5 = 7 -4 = 3 Total turnaround time = 2 + 12 +2 +17+3 = 36 Average turnaround time = 36 / 5 = 7.2

Response time: Response time = (first execution start time) - (arrival time) Response time of P1 = 0 - 0 = 0 Response time of P2 = 7-1=6 Response time of P3 = 2 - 2 = 0 Response time of P4 = 13 - 3 = 10 Response time of P5 = 4 -4 = 0 Total response time = 0 + 6 + 0 + 10 + 0 = 16 Average response time = 16/5 = 3.2

SJFS - PE - Shortest Job First Preemptive

Time-> 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 P1 P5 P2

Waiting time: Waiting time = (execution starting time) - (arrival time OR last execution end time) Waiting time of P1 = 0 - 0 = 0 Waiting time of P2 = 7 - 1 = 6 Waiting time of P3 = 2 - 2 = 0 Waiting time of P4 = 13 - 3 = 10 Waiting time of P5 = 4 - 4 = 0 Total waiting time = 0 + 6 + 0 + 10 + 0 = 16 Average waiting time = 16/5 = 3.2 Turnaround time: Turnaround time = (execution completion time) - (arrival time) Turnaround time of P1 = 2 - 0 = 2 Turnaround time of P2 = 13 - 1 = 12 Turnaround time of P3 = 4 - 2 = 2 Turnaround time of P4 = 20 - 3 = 17 Turnaround time of P5 = 7-4 = 3 Total turnaround time = 2 + 12 +2 +17+3 = 36 Average turnaround time = 36 / 5 = 7.2

Response time: Response time = (first execution start time) - (arrival time) Response time of P1 = 0 - 0 = 0 Response time of P2 = 7-1 = 6 Response time of P3 = 2-2 = 0 Response time of P4 = 13 - 3 = 10 Response time of P5 = 4-4 = 0 Total response time = 0 + 6 +0 + 10 + 0 = 16 Average response time = 16 / 5 = 3.2

RRS - Round Robin Scheduling

Time-> 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 P1 - P2 P3 - P4 P5 P2 P4 P4

Waiting time: Waiting time = (execution starting time) - (arrival time OR last execution end time) Waiting time of P1 = 0 - 0 = 0 Waiting time of P2 = (2-1) + (13-5) = 1 +8 = 9 Waiting time of P3 =5 -2 = 3 Waiting time of P4 = (7-3) + (16 - 10) + (19 - 19) = 4 +6+0 = 10 Waiting time of P5 = 10 -4 = 6 Total waiting time = 0 +9+3+10+ 6 = 28 Average waiting time = 28/5 = 5.6 Turnaround time: Turnaround time = (execution completion time) - (arrival time) Turnaround time of P1 = 2 - 0 = 2 Turnaround time of P2 = 16 - 1 = 15 Turnaround time of P3 = 7 -2=5 Turnaround time of P4 = 20 - 3 =17 Turnaround time of P5 = 13-4=9 Total turnaround time = 2 + 15 + 5 + 17 + 9 = 48 Average turnaround time = 48/5 = 9.6

Response time: Response time = (first execution start time) - (arrival time) Response time of P1 = 0 - 0 = 0 Response time of P2 =2-1=1 Response time of P3 = 5 - 2 = 3 Response time of P4 = 7 - 3 =4 Response time of P5 = 10 - 456 Total response time = 0+1+3 +4 +6 = 14 Average response time = 14/5 = 2.8