Roll No: 160122733303 Exp. No: 07 Date: 22/10/24
WEEK-7
Ps cement Algorithms
4)Aim: Write a program to demonstrate FIFO page replacement algorithm.
Description The FIFO (First1n-First-Out) page replacement algorithm replaces the oldest
page in memory when a new page needs to be loaded and the frame is full. It maintains a
queue, ensuring that the first loaded page is the first to be removed. If the requested page is
not in the frame, a page fault occurs, and the page is added to memory. The goal is to
minimize page faults while simulating memory management.
Code:
def fifo_page_replacement(pages, frame_size):
frame = []
page faults = 0
print("Page\tFrames")
for page in pages:
if page not in frame:
if len(frame) < frame_size:
frame.append(page)
else:
frame. pop(0)
frame.append(page)
page_faults += 1
print({pagel\ t{frame}")
print(f"\nTotal Page Faults: {page_faults}")
pages = 7,0, 1,2, 0,3,0, 4, 2, 3,0,3, 2)
frame_size
fifo_page_replacement(pages, frame_size)
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Exp. No: 07 Date: 22/10/24
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8 Bede Seas
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Signature of the Faculty.....cccsssseeeeseseeee Roll No: 160122733303 Exp. No: 07 Date: 22/10/24
2)Aim: Write a program to demonstrate LRU page replacement algorithm.
Description :LRU (Least Recently Used) replaces the page not accessed for the longest time
when the frame is full. It minimizes page faults by retaining frequently used pages but
requires extra tracking overhead.
Code:
def Iru_page_replacement(pages, frame_size):
frame =[]
‘page_faults = 0
print("Page\Frames")
for page in pages:
if page not in frame:
if len(frame) < frame_size:
frame.append(page)
else:
Itu_page = min(frame, key=lambda p: pages|.pages. index(page)].count{p))
frame.remove(hu_page)
frame.append(page)
page_faults += 1
print({page}\t{frame}")
print(f"nTotal Page Faults: (page_fautts}")
pages =[7, 0, 1, 2, 0, 3, 0 4,2, 3.0, 3,2]
frame_size = 3
Iru_page_replecement(pages, frame_size)
Output:
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age
P:
7
A
rl
a
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3
ry
4
3
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3)Aim: Write a program to demonstrate the optimal page replacement algorithm.
Description: The Optimal algorithm replaces the page that won't be needed for the longest
time in the future. It minimizes page faults but requires future knowledge of page
references, making it ideal only in theoretical or predictive scenarios.
Code:
det optimal_page_replacement(pages, frame_size):
frame = []
page_faults=0
print("Page\'Frames")
for , page in enumerate(pages):
if page not in frame:
if len(trame) < frame_size:
frame.append(page)
else:
future_indices = [(pages[i+1:].index(p) if p in pages|i+1:] else float('inf)) for p in
frame]
frame. pop(future_indices.index(max(future_indices)))
frame.append(page)
page_faults += 1
print(F{page}\t{frame}")
print(f"vnTotal Page Faults: {page_fautts}")
pages =[7, 0, 1, 2, 0, 3, 0, 4, 2, 30,3, 2]
frame_size = 3
optimal_page_replacement(pages, frame_size)
Output:
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bapers seeps < es ey
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4)Aim: Write a program to illustrate threads.
Description: This program demonstrates multithreading in C using the pthread library,
where three threads run concurrently. One thread takes user Input from the keyboard, the
second displays the input multiple times, and the third saves the input to a file. A shared
buffer is used to store input, ensuring that threads can access it. Synchronization is
achieved using pthread_join to make sure input is completed before the other threads run.
This showcases parallel processing with shared data and thread management
Code:
#include
#include
#include // For sleep and getpid
void* takeinputfromkeyboard(void *arg) {
print{("Thread ID: %ilu, Process ID: %d - Taking input from keyboard\n", pthread_self(),
getpid();
for (int i= 0;i <5; i++) {
printf("Thread ID: %lu - Waiting for user input \n", pthread_self());
sleep(1);
J
return NULL:
1
void* displayContent(void *arg) {
printf("Thread ID: %slu, Process ID: %d - Display Content on the screen \n", pthread_self(),
getpid();
for (int i= 0;1 <5; i#+) {
printf("Thread ID: %lu - Display Content \n", pthread_self());
sleep(1);
}
return NULL;
)
void* savingcontentHardisk(void *arg) {
printi("Thread ID: %lu, Process ID: %d - Saving the content\n", pthread _self(), getpid());
for (inti=0;i <5; i++) {
printf("Thread ID: %lu - Saving the content into file \n", pthread_self());
sleep(l);
}
return NULL;
int main() {
pthread_t t, 2, 3;
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pthread _create(éet1, NULL, takeinputfromkeyboard, NULL);
pthread_create(ét2, NULL, displayContent, NULL):
pthread_create(ét3, NULL, savingcontentHardisk, NULL);
pthread _join(t1, NULL);
pthread _join(t2, NULL);
pthread _join(t3, NULL);
return 0;
)
‘Output:
Smt
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