MTech Advanced Operating Systems Lab (14SCS16)(1st sem)
Design and Develop a program to implement lazy buddy system algorithm.
#include<stdio.h>
#include<stdlib.h>
int
tree[2050], i, j, k;
void
segmentalloc(int, int), makedivided(int), makefree(int), printing(int, int);
int
place(int), power(int, int);
int
main()
{
int totsize, ch, req;
printf("BUDDY SYSTEM
REQUIREMENTS");
printf("\n Enter the Size of
the memory : ");
scanf("%d", &totsize);
while(1)
{
printf("\n B U D D
Y S Y S T E M ");
printf("\n 1) Locate the process into the Memory");
printf("\n 2) Remove the process from Memory");
printf("\n 3) Tree structure for Memory allocation
Map");
printf("\n 4) Exit");
printf("\n Enter
your choice : ");
scanf("%d", &ch);
switch(ch)
{
case 1:
printf("\n MEMORY ALLOCATION ");
printf("\n
Enter the Process size : ");
scanf("%d",
&req);
segmentalloc(totsize,
req);
break;
case 2:
printf("\n
MEMORY DEALLOCATION ");
printf("\n
Enter the process size : ");
scanf("%d",
&req);
makefree(req);
break;
case 3:
printf("\n MEMORY ALLOCATION MAP");
printing(totsize, 0);
break;
default: return;
}
}
}
void
segmentalloc(int totsize, int request)
{
int flevel = 0, size;
size = totsize;
if(request > totsize)
{
printf("%c R E S U L T
: ", 2);
printf("\n The
system don't have enough free memory");
printf("\n
Suggession : Go for VIRTUAL MEMORY");
return;
}
while(1)
{
if(request < size
&& request > (size/2))
break;
else
{
size /= 2;
flevel++;
}
}
for(i = power(2, flevel) - 1; i <= (power(2, flevel+1) - 2); i++)
if(tree[i] == 0
&& place(i) )
{
tree[i] = request;
makedivided(i);
printf("\n
Result : Successful Allocation");
break;
}
if(i == power(2, flevel+1)
- 1)
{
printf("
%c Result :
", 2);
printf("\n
The system don't have enough free memory");
printf("\n
Suggession : Go for VIRTUAL Memory Mode");
}
}
void
makedivided(int node)
{
while(node != 0)
{
node = (node%2 == 0) ? (node-1)/2
: node/2;
tree[node] = 1;
}
}
int
place(int node)
{
while(node != 0)
{
node = (node%2 == 0) ? (node-1)/2
: node/2;
if(tree[node] > 1)
return 0;
}
return 1;
}
void
makefree(int request)
{
int node = 0;
while(1)
{
if(tree[node] == request)
break;
else
node++;
}
tree[node] = 0;
while(node!=0)
{
if( tree[node%2==0 ? node-1
: node+1] == 0 && tree[node] == 0)
{
tree[node%2 ==
0? (node-1)/2 : node/2] = 0;
node = node%2
== 0 ? (node-1)/2 : node/2;
}
else
break;
}
}
int
power(int x, int y)
{
int z, ans;
if(y == 0)
return 1;
ans = x;
for(z=1; z<y; z++)
ans *= x;
return ans;
}
void
printing(int totsize, int node)
{
int permission = 0, llimit, ulimit, tab;
if(node == 0)
permission = 1;
else if(node%2 == 0)
permission = tree[(node-1)/2]==1
? 1 : 0;
else
permission = tree[node/2]
== 1 ? 1 : 0;
if(permission)
{
llimit = ulimit = tab = 0;
while(1)
{
if(node >=
llimit && node <= ulimit)
break;
else
{
tab++;
printf(" ");
llimit
= ulimit+1;
ulimit
= 2*ulimit+2;
}
}
printf(" %d ",
totsize/power(2, tab));
if(tree[node] > 1)
printf("--->
Allocated %d ", tree[node]);
else if(tree[node] == 1)
printf("--->
Divided");
else
printf("--->
Free");
printing(totsize, 2*node+1);
printing(totsize, 2*node+2);
}
}
Output:
ubuntu@ubuntu-VirtualBox:~/lab$
gedit 2.c
ubuntu@ubuntu-VirtualBox:~/lab$
cc 2.c
ubuntu@ubuntu-VirtualBox:~/lab$
./a.out
BUDDY
SYSTEM REQUIREMENTS
Enter
the Size of the memory : 500
B U D D Y
S Y S T E M
1)
Locate the process into the Memory
2)
Remove the process from Memory
3) Tree
structure for Memory allocation Map
4)
Exit
Enter your choice : 1
MEMORY ALLOCATION
Enter the Process size : 400
Result : Successful Allocation
B U D D Y
S Y S T E M
1)
Locate the process into the Memory
2)
Remove the process from Memory
3) Tree
structure for Memory allocation Map
4)
Exit
Enter your choice : 3
MEMORY
ALLOCATION MAP 500 ---> Allocated 400
B
U D D Y S Y S T E M
1) Locate the process into the Memory
2) Remove the process from Memory
3) Tree structure for Memory allocation Map
4) Exit
Enter
your choice : 2
MEMORY
DEALLOCATION
Enter
the process size : 400
B U D D Y
S Y S T E M
1)
Locate the process into the Memory
2)
Remove the process from Memory
3) Tree
structure for Memory allocation Map
4)
Exit
Enter your choice :
4
Case 2:
BUDDY SYSTEM REQUIREMENTS
Enter the Size of the memory : 500
B U D D
Y S Y S T E M
1) Locate the process into the Memory
2) Remove the process from Memory
3) Tree structure for Memory allocation Map
4) Exit
Enter your
choice :
1
MEMORY
ALLOCATION
Enter the
Process size : 600
R E S U L
T :
The system
don't have enough free memory
Suggession
: Go for VIRTUAL MEMORY
B U D D
Y S Y S T E M
1) Locate the process into the Memory
2) Remove the process from Memory
3) Tree structure for Memory allocation Map
4) Exit
Enter your
choice :
Case 3:
BUDDY SYSTEM REQUIREMENTS
Enter the Size of the memory : 500
B U D D
Y S Y S T E M
1) Locate the process into the Memory
2) Remove the process from Memory
3) Tree structure for Memory allocation Map
4) Exit
Enter your
choice :
1
MEMORY
ALLOCATION
Enter the
Process size : 100
Result :
Successful Allocation
B U D D
Y S Y S T E M
1) Locate the process into the Memory
2) Remove the process from Memory
3) Tree structure for Memory allocation Map
4) Exit
Enter your
choice :
3
MEMORY
ALLOCATIONMAP 500 ---> Divided 250 ---> Divided
125 ---> Allocated 100 125 ---> Free 250 ---> Free
B U D D
Y S Y S T E M
1) Locate the process into the Memory
2) Remove the process from Memory
3) Tree structure for Memory allocation Map
4) Exit
Enter your
choice : 4
