COSC $354\mathrm{.}002$ Operating Systems

Project $3-$ CPU Scheduling

Points Possible: $100$

There should be no collaboration among students. A student shouldn$$t share any project

code with any other student. Collaborations among students in any form will be treated as a

serious violation of the University's academic integrity code.

Objectives:

$1.$ Complete the source code to simulate CPU scheduling.

$2.$ Build a binary program on a Linux machine.

$3.$ Run the program and record the result of the simulation.

$3.$ Manage the scheduling algorithms Round Robin with priority used in this project.

Requirements:

$$ Each student should independently accomplish this project assignment. You may

discuss with other students to solve the coding problems.

$$ Important! Read the I$/$O format specification carefully and follow. It is very important to

your final grade of this project!

$$ Important! The project must be executed on a Linux operating system. Use the CentOS

virtual machine configured in Project $1$ or any other Linux operating system.

$1.$ Introduction to Round Robin Schedule with a Priority

Round Robin $($RR$)$ with a priority is a CPU scheduling algorithm where each process is

assigned a fixed time slot in a cyclic way.

Assume there are $5$ processes with a structure of a Process Control Block $($PCB$)$:

$1.$ Process ID: identify each process.

$2.$ Priority: integer $0-100,$ the bigger the number is$,$ the higher the priority is$.$ The number

will be decreased by $1$ once a process has done for a quantum.

$3.$ Execution time $($user input$)$: how many ms a process needs.

$4.$ Status: Ready$($initialized$),$ Terminated and currently running. Represented by letter $"$R$",$

$"$F$"$ and $"$r$"$ respectively.

To simplify our simulation, we assume all the $5$ processes arrive at the same time $0.$ Also, we do

not require you to implement a cyclic linked list to connect all $5$ processes structure using

pointers. We define the structure of PCB in source code and simply store them in an array, and

looping each PCB every time we use them

$2.$ Follow the Format Specification $(10$ Points$)$

In the source file "Firstname$\_$Lastname.c$",$ you will find first four comment lines:

$//$ #$0$#BEGIN# DO NOT MODIFY THIS COMMENT LINE!

$//$ Firstname

$//$ Lastname

$//$ #$0$#END# DO NOT MODIFY THIS COMMENT LINE!

Your first task is modifying the two lines between the beginning line and end line. Change them

into your first name and last name. Remember the strings are case$-$sensitive$,$ so capitalize the

first letter of the word and follow exactly the syntax of the example.

You can see lots of similar code blocks in the file. You are free and supposed to fill your answer

between those special beginning and ending comment lines. You can insert and edit multiple

lines between special comment lines in anyways, however$($Important$!),$ as the comment

indicated, do not modify the special begin and comment lines themselves!

Let's do the second task. Scroll down to the bottom of the file and find those lines $($press "shift $+$

g$"$ if you are using vi$/$vim$)$:

$//$ #$9$#BEGIN# DO NOT MODIFY THIS COMMENT LINE!

banner$\_$id $=12345678$;

$//$ #$9$#END# DO NOT MODIFY THIS COMMENT LINE!

Look at your student ID card, check your banner ID$.$ Again, change the "banner$\_$id$"$ value to

your own ID$.$ Your unique student id will be compiled into the program, and the input of the

experiment also uniquely depends on your ID$.$

Warning: Since every student has a unique id number, the later compiled binary file is also

unique. Copy binary file from other students will be easily detected!

$3.$ Complete Source Code $(60$ Points$)$

Read the source code and rest comments, try to understand the function of each line of code.

Follow the instructions in the comments and insert proper code into the rest $8$ blocks to

implement a CPU scheduling with RR$/$Priority$.($C$/$C$++$ files are acceptable$).$ Read the

requirements carefully, because some blocks require exact syntax.

$4.$ Run and Record Simulation Result $(20$ Points$)$

Compile your source code into a binary program. For example, use following command

$ gcc Firstname$\_$Lastname.c $-$o Firstname$\_$Lastname

You can run the program and set$-$up any condition you wish to simulate.

$ $./$Firstname$\_$Lastname

Play the program for a while and observe how it works. Now we run a specific simulation: $(1)$

take the last five digits reversed and set them as the priority $(2)$ set their running time $1,2,3,4,$

$5$ respectively. $(3)$ Gives any five id your like to the $5$ processes

For example, there is a banner id $03900281,$ then the last $5$ reversed digits $1,8,2,0,0.$ and

I call $5$ process $"$AA$","$BB$","$CC$","$DD$","$EE$",$ then my entire setup for $5$ process will be:

process id priority running time

AA $11$

BB $82$

CC $23$

DD $04$

EE $05$

We have already learned instructions of how to use command script recording commands in the

terminal in project $1,$ here we use the script command to record.

$ script Firstname$\_$Lastname.script

Script started, file is typescript

$ $./$Firstname$\_$Lastname

banner$\_$id: $903900281$

ID PRIORITY RUNTIME$--->$PCB$[0]$

$\_$

The program starts running and waits for your inputs. In this example, according to my set$-$up of

processes, my first line input as following:

$ AA $11$

Press enter and finish the rest lines of input. Following the instructions are given by the program

and run the program until the end. Then exit recording and save it into typescript file

"Firstname$\_$Lastname.script" by the following command

$ exit

exit Script done, file is Firstname$\_$Lastname.script

Warning: Since every student has a unique id number, the result of the simulation is also unique.

Copy simulation results from other students will be easily detected!

$5.$ Deliverables $(10$ Points$)$

Since you have generated multiple script files, please save all the script files in one

directory. Create a folder "Firstname$\_$Lastname" first. Please make sure the folder name in

correct form. You can use the command mv to rename the folder:

$ mv folder$-$name Firstname$\_$Lastname

Make sure all the three files are into this folder. You should have those following files inside the

folder:

$1.$ commands recording file: Firstname$\_$Lastname.script

$2.$ executable binary file: Firstname$\_$Lastname

$3.$ source code file: Firstname$\_$Lastname.c

Achieve all the folder into a single tarred and compressed file with a tar command.

tar $-$zcvf Firstname$\_$Lastname.tar.gz Firstname$\_$Lastname

You need to submit one tarred file with a format: Firstname$\_$Lastname.tar.gz

Grading Criteria:

$1.$ Follow the format specification: $10\%$

a$.$ Do not break the special comments.

b$.$ Input your name properly $($mark #$0).$

c$.$ Input your banner id properly $($mark #$9).$

$2.$ Complete the source code: $60\%$

a$.$ mark #$1$ ~ #$8.$

b$.$ See detailed specifications for each blank in the source code file.

$3.$ Compiling and running result: $20\%$

a$.$ Compile the code successfully.

b$.$ Running the program properly depends on your ID$.$

c$.$ Record the running results.

$4.$ Deliverables: $10\%$

a$.$ Contains all the files.

b$.$ Naming all the files properly