Name: - sumit kumar
Subject: - operating system
Roll No.: -23020570053
Submitted to: -Ms. Shital
Index of Practicals
1. Execution of Various LINUX Commands:
• i. Information Maintenance:
o wc
o clear
o cal
o who
o date
o pwd
• ii. File Management:
o cat
o cp
o rm
o mv
o cmp
o comm
o diff
o find
o grep
o awk
• iii. Directory Management:
o cd
o mkdir
o rmdir
o ls
2. Execution of Various LINUX Commands:
• i. Process Control:
o fork
o getpid
o ps
o kill
o sleep
• ii. Communication:
o Input-output redirection
o Pipe
• iii. Protection Management:
o chmod
o chown
o chgrp
3. Program using fork() and/or exec():
• i. Parent and child execute same program, same code.
• ii. Parent and child execute same program, different code.
• iii. Parent waits for child to finish before terminating.
4. Report Behavior of Linux Kernel (Kernel Version, CPU Type, and CPU Information)
5. Report Behavior of Linux Kernel (Memory Information, Configured Memory, Free/Used
Memory)
6. Program to Copy Files Using System Calls
7. Implementation of FCFS Scheduling Algorithm
8. Implementation of SJF Scheduling Algorithm
9. Implementation of Non-preemptive Priority-based Scheduling Algorithm
10. Implementation of SRTF Scheduling Algorithm
11. Calculate Sum of n Numbers Using Pthreads
• Divide n numbers into two smaller lists.
• Use two separate threads to sum the sub-lists.
12. Implementation of First-fit, Best-fit, and Worst-fit Allocation Strategies
Acknowledgment
I would like to express my sincere gratitude to
my instructor, Mrs. Sheetal Singh, for providing
me with the opportunity to work on this series
of practicals. Their invaluable guidance and
support have been instrumental in
understanding the core concepts of Operating
Systems.
I would also like to thank Ramanujan College,
University of Delhi, for offering such a rich
curriculum that fosters technical learning and
hands-on experience. The practical applications
of various algorithms and transformation
techniques have deepened my knowledge in the
field.
Furthermore, I would like to thank my peers for
their encouragement and collaboration during
the course of this project. Their inputs have
enhanced my learning experience and
contributed to a stimulating environment for
problem-solving.
1. Execute various LINUX commands for:
i. Information Maintenance: wc, clear, cal,
who, date, pwd.
ii. File Management: cat, cp, rm, mv, cmp,
comm, diff, find, grep, awk.
iii. Directory Management: cd, mkdir, rmdir, ls.
Outputs:
i. Information Maintenance
wc(word count)
Clear (clears the terminal)
Cal(Shows calender)
Who(The who command is a simple and
effective way to display information about
currently logged-in users.)
Date(shows Date)
Pwd(displays the current working directory's
full path)
ii. File Management:
cat(a tool for working with files and their
contents)
Cp(Copies content of files)
Rm(removes files)
mv(used to move and rename files and
directories)
,
cmp(Compares two files byte-by-byte.)
Comm(Compares two sorted files line-by-line.)
Diff(Shows line-by-line differences between
files.)
, find(Finds files/directories in a directory
hierarchy.)
, grep(Searches for patterns in files.)
, awk(Text-processing tool for structured
data.).
iii. Directory Management:
cd(Changes the current directory.).
mkdir,
rmdir,
ls.
Q2.Execute various LINUX commands for:
i. Process Control: fork, getpid, ps, kill,
sleep
ii. Communication: Input-output
redirection, Pipe
iii. Protection Management: chmod,
chown, chgrp
Output:
i. Process Control:
1. fork(): Used to create a new process
by duplicating the calling process. It’s
a system call, so it won't be executed
directly in the shell, but through C
programming.
Example in C:
#include <stdio.h>
#include <unistd.h>
int main() {
pid_t pid = fork();
if (pid == 0) {
printf("This is the child process\n");
} else {
printf("This is the parent process\n");
}
return 0;
}
2. getpid(): Gets the process ID of the
calling process. Like fork(), this is used
in C programming.
Example in C:
c
#include <stdio.h>
#include <unistd.h>
int main() {
printf("Process ID: %d\n", getpid());
return 0;
}
3. ps: Shows information about active
processes. The basic command is:
ps
4. kill: Sends a signal to a process. It
is commonly used to terminate a
process.
5. sleep: Pauses the execution of a
script or process for a specified time
(in seconds).
ii. Communication:
1. Input-output redirection: Allows
you to redirect the input and output of
commands to/from files or other
streams.
2. Pipe: Allows you to send the output
of one command to another command
as input.
iii. Protection Management:
1. chmod: Changes the file
permissions.
o To give read (r), write (w), and
execute (x) permissions to the
owner and read and execute
permissions to the group and
others.
o To add execute permission for the
user.
2. chown: Changes the ownership of a
file.
o Change owner to user1 and group to
group1:
3. chgrp: Changes the group
ownership of a file.
o Change the group of a file to
group1:
These commands help in managing
processes, communication between
processes, and setting file permissions and
ownership in Linux.
Q3. Write a program (using fork () and/or
exec () commands) where parent and child
execute:
i. same program, same code.
ii. same program, different
code.
iii. before terminating, the
parent waits for the child to
finish its task
Code: (i)
#include <iostream>
#include <unistd.h>
#include <sys/wait.h>
int main() {
pid_t pid = fork(); // Create child process
if (pid == 0) { // Child process
std::cout << "This is the child process with PID " <<
getpid() << std::endl;
} else { // Parent process
std::cout << "This is the parent process with PID " <<
getpid() << std::endl;
wait(NULL); // Wait for child to finish
}
return 0;
}
Output:
Code(ii):
#include <iostream>
#include <unistd.h>
#include <sys/wait.h>
int main() {
pid_t pid = fork(); // Create child process
if (pid == 0) { // Child process
std::cout << "This is the child process with PID " <<
getpid() << std::endl;
// Child performs a different task
std::cout << "Child: Executing different code!" <<
std::endl;
} else { // Parent process
std::cout << "This is the parent process with PID " <<
getpid() << std::endl;
// Parent performs its task
std::cout << "Parent: Executing different code!" <<
std::endl;
wait(NULL); // Wait for child to finish
}
return 0;
}
Output:
Code(iii):
#include <iostream>
#include <unistd.h>
#include <sys/wait.h>
int main() {
pid_t pid = fork(); // Create child process
if (pid == 0) { // Child process
std::cout << "Child process with PID " << getpid() << "
started." << std::endl;
sleep(2); // Simulating work in child
std::cout << "Child process finished." << std::endl;
} else { // Parent process
std::cout << "Parent process with PID " << getpid() << "
started." << std::endl;
wait(NULL); // Wait for child to finish
std::cout << "Parent process resumed after child
finished." << std::endl;
}
return 0;
}
Output:
4. Write a program to report behaviour of
Linux kernel including kernel version, CPU
type and CPU information.
Code:
#include <iostream>
#include <cstdlib>
using namespace std;
int main() {
cout << "Kernel Version and Information:" << endl;
system("uname -r");
cout << "\nCPU Information:" << endl;
system("lscpu");
return 0;
}Output:
5. Write a program to report behaviour of
Linux kernel including information on
configured memory, amount of free and
used memory. (Memory information)
Code:
#include <iostream>
#include <cstdlib>
int main() {
std::cout << "Memory Information:" << std::endl;
system("free -h");
return 0;
}
Output:
6. Write a program to copy files using
system calls.
Code:
#include <iostream>
#include <fcntl.h>
#include <unistd.h>
int main() {
const char* source = "source.txt";
const char* destination = "destination.txt";
int src = open(source, O_RDONLY);
if (src == -1) {
std::cerr << "Error opening source file!" << std::endl;
return 1;
}
int dest = open(destination, O_WRONLY | O_CREAT |
O_TRUNC, 0644);
if (dest == -1) {
std::cerr << "Error opening destination file!" <<
std::endl;
close(src);
return 1;
}
char buffer[1024];
ssize_t bytesRead;
while ((bytesRead = read(src, buffer, sizeof(buffer))) > 0) {
write(dest, buffer, bytesRead);
}
close(src);
close(dest);
std::cout << "File copied successfully!" << std::endl;
return 0;
}
Output:
(because there is no source file present)
7. Write a program to implement FCFS
scheduling algorithm.
Code:
#include <iostream>
#include <vector>
#include <algorithm> // For std::sort
struct Process {
int id, arrival_time, burst_time;
};
// Comparison function to sort processes by arrival time
bool compareByArrival(const Process& a, const Process&
b) {
return a.arrival_time < b.arrival_time;
}
int main() {
int n;
std::cout << "Enter number of processes: ";
std::cin >> n;
std::vector<Process> processes(n);
for (int i = 0; i < n; ++i) {
std::cout << "Enter arrival time and burst time for
process " << i + 1 << ": ";
std::cin >> processes[i].arrival_time >>
processes[i].burst_time;
processes[i].id = i + 1;
}
// Sort processes by arrival time
std::sort(processes.begin(), processes.end(),
compareByArrival);
int time = 0;
std::cout << "\nProcess Execution Order (FCFS):\n";
for (const auto& p : processes) {
if (time < p.arrival_time)
time = p.arrival_time; // Wait for the process to arrive
time += p.burst_time; // Execute the process
std::cout << "P" << p.id << " (Arrival: " << p.arrival_time
<< ", Burst: " << p.burst_time << ")\n";
}
return 0;
}
Output:
8. Write a program to implement SJF
scheduling algorithm.
Code:
#include <iostream>
#include <vector>
#include <algorithm>
struct Process {
int id, burst_time, waiting_time, turnaround_time;
};
bool compare(Process p1, Process p2) {
return p1.burst_time < p2.burst_time;
}
int main() {
int n;
std::cout << "Enter number of processes: ";
std::cin >> n;
std::vector<Process> processes(n);
for (int i = 0; i < n; ++i) {
std::cout << "Enter burst time for process " << i + 1 <<
": ";
std::cin >> processes[i].burst_time;
processes[i].id = i + 1;
}
std::sort(processes.begin(), processes.end(), compare);
int time = 0;
double total_wt = 0, total_tat = 0;
std::cout << "Process Execution Order (SJF):\n";
for (auto& p : processes) {
p.waiting_time = time;
p.turnaround_time = p.waiting_time + p.burst_time;
time += p.burst_time;
total_wt += p.waiting_time;
total_tat += p.turnaround_time;
std::cout << "P" << p.id << " (Burst: " << p.burst_time
<< ", Waiting Time: " << p.waiting_time
<< ", Turnaround Time: " << p.turnaround_time <<
")\n";
}
std::cout << "Average Waiting Time: " << total_wt / n <<
std::endl;
std::cout << "Average Turnaround Time: " << total_tat / n
<< std::endl;
return 0;
}
Output:
9. Write a program to implement non-
preemptive priority-based scheduling
algorithm.
Code:
#include <iostream>
#include <vector>
#include <algorithm>
struct Process {
int id, burst_time, priority, waiting_time,
turnaround_time;
};
bool compare(Process p1, Process p2) {
return p1.priority < p2.priority;
}
int main() {
int n;
std::cout << "Enter number of processes: ";
std::cin >> n;
std::vector<Process> processes(n);
for (int i = 0; i < n; ++i) {
std::cout << "Enter burst time and priority for process "
<< i + 1 << ": ";
std::cin >> processes[i].burst_time >>
processes[i].priority;
processes[i].id = i + 1;
}
std::sort(processes.begin(), processes.end(), compare);
int time = 0;
double total_wt = 0, total_tat = 0;
std::cout << "Process Execution Order (Priority
Scheduling):\n";
for (auto& p : processes) {
p.waiting_time = time;
p.turnaround_time = p.waiting_time + p.burst_time;
time += p.burst_time;
total_wt += p.waiting_time;
total_tat += p.turnaround_time;
std::cout << "P" << p.id << " (Burst: " << p.burst_time
<< ", Priority: " << p.priority
<< ", Waiting Time: " << p.waiting_time
<< ", Turnaround Time: " << p.turnaround_time <<
")\n";
}
std::cout << "Average Waiting Time: " << total_wt / n <<
std::endl;
std::cout << "Average Turnaround Time: " << total_tat / n
<< std::endl;
return 0;
}
Output:
10. Write a program to implement SRTF
scheduling algorithm.
Code:
#include <iostream>
#include <vector>
#include <algorithm>
#include <climits>
struct Process {
int id, arrival_time, burst_time, remaining_time,
completion_time, waiting_time, turnaround_time;
};
bool compareArrivalTime(Process p1, Process p2) {
return p1.arrival_time < p2.arrival_time;
}
int main() {
int n;
std::cout << "Enter number of processes: ";
std::cin >> n;
std::vector<Process> processes(n);
for (int i = 0; i < n; ++i) {
std::cout << "Enter arrival time and burst time for
process " << i + 1 << ": ";
std::cin >> processes[i].arrival_time >>
processes[i].burst_time;
processes[i].id = i + 1;
processes[i].remaining_time =
processes[i].burst_time; // Initialize remaining time
}
// Sort processes based on arrival time
std::sort(processes.begin(), processes.end(),
compareArrivalTime);
int currentTime = 0, completed = 0;
float totalWaitingTime = 0, totalTurnaroundTime = 0;
std::vector<bool> isCompleted(n, false);
// Execute processes until all are completed
while (completed < n) {
int shortestProcess = -1;
int minRemainingTime = INT_MAX;
// Find the process with the shortest remaining time
that has arrived
for (int i = 0; i < n; ++i) {
if (!isCompleted[i] && processes[i].arrival_time <=
currentTime && processes[i].remaining_time <
minRemainingTime) {
minRemainingTime = processes[i].remaining_time;
shortestProcess = i;
}
}
if (shortestProcess != -1) {
// Process the shortest job
processes[shortestProcess].remaining_time--;
currentTime++;
// If the process is completed
if (processes[shortestProcess].remaining_time == 0)
{
processes[shortestProcess].completion_time =
currentTime;
processes[shortestProcess].turnaround_time =
processes[shortestProcess].completion_time -
processes[shortestProcess].arrival_time;
processes[shortestProcess].waiting_time =
processes[shortestProcess].turnaround_time -
processes[shortestProcess].burst_time;
totalWaitingTime +=
processes[shortestProcess].waiting_time;
totalTurnaroundTime +=
processes[shortestProcess].turnaround_time;
isCompleted[shortestProcess] = true;
completed++;
}
} else {
// If no process is ready to execute, increment time
currentTime++;
}
}
// Output the results
std::cout << "\nProcess execution details (SRTF
Scheduling):\n";
for (const auto& p : processes) {
std::cout << "P" << p.id << " (Arrival Time: " <<
p.arrival_time
<< ", Burst Time: " << p.burst_time
<< ", Completion Time: " << p.completion_time
<< ", Turnaround Time: " << p.turnaround_time
<< ", Waiting Time: " << p.waiting_time << ")\n";
}
std::cout << "\nAverage Waiting Time: " <<
totalWaitingTime / n << std::endl;
std::cout << "Average Turnaround Time: " <<
totalTurnaroundTime / n << std::endl;
return 0;}
Output:
11. Write a program to calculate sum of n
numbers using Pthreads. A list of n
numbers is divided into two smaller list of
equal size, two separate threads are used
to sum the sub lists.
Code:
#include <iostream>
#include <pthread.h>
#include <vector>
struct ThreadData {
std::vector<int>* data;
int start, end;
int sum;
};
void* sum_partial(void* arg) {
ThreadData* td = (ThreadData*)arg;
td->sum = 0;
for (int i = td->start; i < td->end; ++i) {
td->sum += (*td->data)[i];
}
return nullptr;
}
int main() {
int n;
std::cout << "Enter number of elements: ";
std::cin >> n;
std::vector<int> data(n);
std::cout << "Enter the numbers:\n";
for (int i = 0; i < n; ++i) {
std::cin >> data[i];
}
pthread_t threads[2];
ThreadData td1 = {&data, 0, n / 2, 0};
ThreadData td2 = {&data, n / 2, n, 0};
pthread_create(&threads[0], nullptr, sum_partial, &td1);
pthread_create(&threads[1], nullptr, sum_partial, &td2);
pthread_join(threads[0], nullptr);
pthread_join(threads[1], nullptr);
int total_sum = td1.sum + td2.sum;
std::cout << "Total sum: " << total_sum << std::endl;
return 0;
}
Output:
12. Write a program to implement first-fit,
best-fit and worst-fit allocation strategies.
Code:
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
// Function to display memory allocation
void displayAllocation(const vector<int>& blockSize,
const vector<int>& processSize, const vector<int>&
allocation) {
cout << "Process No.\tProcess Size\tBlock No.\tBlock
Size\n";
for (size_t i = 0; i < allocation.size(); ++i) {
if (allocation[i] != -1) {
cout << " " << i + 1 << "\t\t" << processSize[i]
<< "\t\t" << allocation[i] + 1 << "\t\t" <<
blockSize[allocation[i]] << endl;
} else {
cout << " " << i + 1 << "\t\t" << processSize[i] <<
"\t\tNot Allocated\n";
}
}
}
// First-Fit Memory Allocation
vector<int> firstFit(const vector<int>& blockSize, const
vector<int>& processSize) {
vector<int> allocation(processSize.size(), -1); // -1
means not allocated
vector<int> blocks = blockSize;
for (size_t i = 0; i < processSize.size(); ++i) {
for (size_t j = 0; j < blocks.size(); ++j) {
if (blocks[j] >= processSize[i]) {
allocation[i] = j;
blocks[j] -= processSize[i]; // Reduce the available
block size
break;
}
}
}
return allocation;
}
// Best-Fit Memory Allocation
vector<int> bestFit(const vector<int>& blockSize, const
vector<int>& processSize) {
vector<int> allocation(processSize.size(), -1); // -1
means not allocated
vector<int> blocks = blockSize;
for (size_t i = 0; i < processSize.size(); ++i) {
int bestIdx = -1;
for (size_t j = 0; j < blocks.size(); ++j) {
if (blocks[j] >= processSize[i]) {
if (bestIdx == -1 || blocks[bestIdx] > blocks[j]) {
bestIdx = j;
}
}
}
if (bestIdx != -1) {
allocation[i] = bestIdx;
blocks[bestIdx] -= processSize[i]; // Reduce the
available block size
}
}
return allocation;
}
// Worst-Fit Memory Allocation
vector<int> worstFit(const vector<int>& blockSize, const
vector<int>& processSize) {
vector<int> allocation(processSize.size(), -1); // -1
means not allocated
vector<int> blocks = blockSize;
for (size_t i = 0; i < processSize.size(); ++i) {
int worstIdx = -1;
for (size_t j = 0; j < blocks.size(); ++j) {
if (blocks[j] >= processSize[i]) {
if (worstIdx == -1 || blocks[worstIdx] < blocks[j]) {
worstIdx = j;
}
}
}
if (worstIdx != -1) {
allocation[i] = worstIdx;
blocks[worstIdx] -= processSize[i]; // Reduce the
available block size
}
}
return allocation;
}
int main() {
// Sample input for memory blocks and processes
vector<int> blockSize = {100, 500, 200, 300, 600}; //
Block sizes
vector<int> processSize = {212, 417, 112, 426}; //
Process sizes
// First-Fit Allocation
vector<int> firstFitAlloc = firstFit(blockSize,
processSize);
cout << "First-Fit Allocation:\n";
displayAllocation(blockSize, processSize, firstFitAlloc);
// Best-Fit Allocation
vector<int> bestFitAlloc = bestFit(blockSize,
processSize);
cout << "\nBest-Fit Allocation:\n";
displayAllocation(blockSize, processSize, bestFitAlloc);
// Worst-Fit Allocation
vector<int> worstFitAlloc = worstFit(blockSize,
processSize);
cout << "\nWorst-Fit Allocation:\n";
displayAllocation(blockSize, processSize, worstFitAlloc);
return 0;
}
Output:
