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@pallabpain
Created October 20, 2014 18:23
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Page Replacement simulation in Python
a = []
#Function to accept reference string and frame size.
def accept():
global a,n,m
n = input("\n Enter the size of reference string : ")
for i in range(n):
a.append(input(" Enter [%2d] : " % (i+1)))
m = input("\n Enter page frame size : ")
#First In First Out Page Replacement Algorithm
def __fifo():
global a,n,m
f = -1
page_faults = 0
page = []
for i in range(m):
page.append(-1)
for i in range(n):
flag = 0
for j in range(m):
if(page[j] == a[i]):
flag = 1
break
if flag == 0:
f=(f+1)%m
page[f] = a[i]
page_faults+=1
print "\n%d ->" % (a[i]),
for j in range(m):
if page[j] != -1:
print page[j],
else:
print "-",
else:
print "\n%d -> No Page Fault" % (a[i]),
print "\n Total page faults : %d." % (page_faults)
#Least Recently Used Page Replacement Algorithm
def __lru():
global a,n,m
x = 0
page_faults = 0
page = []
for i in range(m):
page.append(-1)
for i in range(n):
flag = 0
for j in range(m):
if(page[j] == a[i]):
flag = 1
break
if flag == 0:
if page[x] != -1:
min = 999
for k in range(m):
flag = 0
j = i
while j>=0:
j-=1
if(page[k] == a[j]):
flag = 1
break
if (flag == 1 and min > j):
min = j
x = k
page[x] = a[i]
x=(x+1)%m
page_faults+=1
print "\n%d ->" % (a[i]),
for j in range(m):
if page[j] != -1:
print page[j],
else:
print "-",
else:
print "\n%d -> No Page Fault" % (a[i]),
print "\n Total page faults : %d." % (page_faults)
#Optimal Page Replacement Algorithm
def __optimal():
global a,n,m
x = 0
page_faults = 0
page = []
for i in range(m):
page.append(-1)
for i in range(n):
flag = 0
for j in range(m):
if(page[j] == a[i]):
flag = 1
break
if flag == 0:
if page[x] != -1:
max = -1
for k in range(m):
flag = 0
j = i
while j<n:
j+=1
if(page[k] == a[j]):
flag = 1
break
if (flag == 1 and min < j):
max = j
x = k
page[x] = a[i]
x=(x+1)%m
page_faults+=1
print "\n%d ->" % (a[i]),
for j in range(m):
if page[j] != -1:
print page[j],
else:
print "-",
else:
print "\n%d -> No Page Fault" % (a[i]),
print "\n Total page faults : %d." % (page_faults)
#Displaying the menu and calling the functions.
while True:
print "\n SIMULATION OF PAGE REPLACEMENT ALGORITHM"
print " Menu:"
print " 0. Accept."
print " 1. FIFO."
print " 2. LRU."
print " 3. Optimal."
print " 4. Exit."
ch = input(" Select : ")
if ch == 0:
accept()
if ch == 1:
__fifo()
if ch == 2:
__lru()
if ch == 3:
__optimal()
if ch == 4:
break
@andreacasanova
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Hi friend!!
In my simulation I must enter the following command-line parameters:
• Maximum number of frames
• Minimum number of frames per process
• Number of processes
• Process Size (remember that the number of frames to allocate is --- ai = (Si/sum Si)x m --- where Si=process size in pages and m=number of frames avaible
• The length of the reference sequence

Could you tell me how to change the accept function?

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