FIFO Anomaly,,

[mai]

Hi everyone,
i'm trying to exhibit FIFO anomaly(page replacement algorithm),, I
searched over 2000 random strings but i couldnt find any anomaly,, am
i I doing it right?,, Please help,,,The following is the code,,

#include <iostream>
#include <string>
#include <stdio.h>
#include <stdlib.h>
#include <ctime> // For time()
#include <cstdlib> // For srand() and rand()
using namespace std;

struct mem
{
int page;
int extr;
};
mem* memArr;
mem temp;
int* refPattern;
int b_val;
int* arra;

// This is a function that counts the page faults
int PageFaultCount(int noframe, int leng_patt){
int page_fault_num = 0;
int i,j,k,x,y,d,c;
int boolValue = 0;
int boo = 0;

memArr = (mem*)malloc(noframe*sizeof(mem));
memArr[0].extr = 1;
memArr[0].page = refPattern[0];
page_fault_num = 1;
d = 1;
c = 1;
while ((c < leng_patt) && (d < noframe)){
boo = 0;
for(k=0; k<d; k++){
if (memArr[k].page == refPattern[c]){
boo++;
}
}
if(boo == 0){
memArr[d].extr = 0;
memArr[d].page = refPattern[c];
page_fault_num++;
for(j=0; j<=d; j++){
memArr[j].extr = memArr[j].extr + 1;
}
d++;
}
c++;
}
while ((c < leng_patt)&&(d == noframe)){

boolValue = 0;
for(j=0; j< noframe; j++){


if (memArr[j].page == refPattern[c]){
boolValue++;
}
}
if(boolValue == 0){
for(x=0 ; x<(noframe-1); x++){
for(y=(x+1) ; y < noframe ; y++){
if(memArr[x].extr > memArr[y].extr){
temp = memArr[x];
memArr[x] = memArr[y];
memArr[y] = temp;
}
}
}
memArr[noframe-1].page = refPattern[c];
memArr[noframe-1].extr = 0;
page_fault_num++;
for(k=0; k < noframe; k++){
memArr[k].extr = memArr[k].extr + 1;
}
}
c++;
}

return page_fault_num;
}
// this is a function that generate random strings
void GenReferencePatternAndCountPageFault(int num_of_frames, int
num_of_pages, int length_of_ref_patt){

int a[20];
int i,j,x,y,k;
int min = 0;

refPattern = (int*)malloc(length_of_ref_patt*sizeof(int));
//create random reference string

for(i=0; i<length_of_ref_patt; i++)
refPattern = (rand()% num_of_pages) + min;

// here i'm trying to save all the page faults in an array
for(j = 1; j<= num_of_frames; j++){
arra[j-1]= PageFaultCount(j ,length_of_ref_patt);

}
// and here im trying to find if a larger frame has larger page
fault to detect the anomaly
for(x=0 ; x<(num_of_frames-1); x++){
for(y=(x+1) ; y < num_of_frames ; y++){
if(a[x] < a[y]){
b_val = 1;


}
}
}



}


int main(){
int ref_pattern_length, page_count,frame_count_limit, j;

int i =1;
b_val = 0;


cout<<"Please enter the value of frame count limit";
cin>> frame_count_limit;
cout<<"Please enter the value page count :";
cin>> page_count;
cout<<"Please enter the length of reference pattern: ";
cin>> ref_pattern_length;
arra = (int*)malloc(frame_count_limit*sizeof(int));

srand(time(0));
while((i<=2000)&&(b_val == 0)){

GenReferencePatternAndCountPageFault(frame_count_limit,
page_count, ref_pattern_length);
i++;
}
if(b_val == 1){
cout<< "There is a FIFO anomaly
}
else
if(b_val == 0){
cout<<" no anomaly was detected; please try again with different
input \n";}

free(refPattern);
free(arra);
return 0;
}

 

[Howard]

Hi everyone,
i'm trying to exhibit FIFO anomaly(page replacement algorithm),, I
searched over 2000 random strings but i couldnt find any anomaly,, am
i I doing it right?,, Please help,,,The following is the code,,

I'm not sure how many people here would have any idea what a "FIFO anomaly"
is. I sure don't.

We don't know what input you're using, or what you expect the output to be
for any given input. Perhaps you could give us a specific example of some
input, its expected result, and what you're seeing instead. You should also
use a debugger to step through the code and see what it's doing at various
stages. Or add some output statements at various points to report what it's
doing. (Or both.)

-Howard