TASK: DESCRIPTION One of the simplest methods for memory allocation is to divide memory into several fixed-sized partitions. Each partition may contain exactly one process. In this multiple-partition method, when a partition is free, a process is selected from the input queue and is loaded into the free partition. When the process terminates, the partition becomes available for another process. The operating system keeps a table indicating which parts of memory are available and which are occupied. Finally, when a process arrives and needs memory, a memory section large enough for this process is provided. When it is time to load or swap a process into main memory, and if there is more than one free block of memory of sufficient size, then the operating system must decide which free block to allocate. Best-fit strategy chooses the block that is closest in size to the request. First-fit chooses the first available block that is large enough. Worst-fit chooses the largest available block. PROGRAM FIRST-FIT #include #include #define max 25 void main() { int frag[max],b[max],f[max],i,j,nb,nf,temp; static int bf[max],ff[max]; clrscr(); printf("\n\tMemory Management Scheme - First Fit"); printf("\nEnter the number of blocks:"); scanf("%d",&nb); printf("Enter the number of files:"); scanf("%d",&nf); printf("\nEnter the size of the blocks:-\n");for(i=1;i<=nb;i++) { printf("Block %d:",i); scanf("%d",&b[i]); } printf("Enter the size of the files :-\n");for(i=1;i<=nf;i++) { printf("File %d:",i); scanf("%d",&f[i]); } for(i=1;i<=nf;i++) { for(j=1;j<=nb;j++) { if(bf[j]!=1) { temp=b[j]-f[i]; if(temp>=0) { ff[i]=j; break; } } } frag[i]=temp; bf[ff[i]]=1; } printf("\nFile_no:\tFile_size :\tBlock_no:\tBlock_size:\tFragement"); for(i=1;i<=nf;i++) printf("\n%d\t\t%d\t\t%d\t\t%d\t\t%d",i,f[i],ff[i],b[ff[i]],frag[i]); getch(); } INPUT Enter the number of blocks: 3 Enter the number of files: 2 Enter the size of the blocks:- Block 1: 5 Block 2: 2 Block 3: 7 Enter the size of the files:- File 1: 1 File 2: 4 OUTPUT File No File Size Block No Block Size Fragment 1 1 1 5 4 2 4 3 7 3 BEST-FIT #include #include #define max 25 void main() { int frag[max],b[max],f[max],i,j,nb,nf,temp,lowest=10000; static int bf[max],ff[max]; clrscr(); printf("\nEnter the number of blocks:"); scanf("%d",&nb); printf("Enter the number of files:"); scanf("%d",&nf); printf("\nEnter the size of the blocks:-\n");for(i=1;i<=nb;i++) printf("Block %d:",i);scanf("%d",&b[i]); printf("Enter the size of the files :-\n");for(i=1;i<=nf;i++) { printf("File %d:",i); scanf("%d",&f[i]); } for(i=1;i<=nf;i++) { for(j=1;j<=nb;j++) { if(bf[j]!=1) { temp=b[j]-f[i];if(temp>=0) if(lowest>temp) { ff[i]=j; lowest=temp; } } } frag[i]=lowest; bf[ff[i]]=1; lowest=10000; } printf("\nFile No\tFile Size \tBlock No\tBlock Size\tFragment"); for(i=1;i<=nf && ff[i]!=0;i++) printf("\n%d\t\t%d\t\t%d\t\t%d\t\t%d",i,f[i],ff[i],b[ff[i]],frag[i]); getch(); } INPUT Enter the number of blocks: 3 Enter the number of files: 2 Enter the size of the blocks:- Block 1: 5 Block 2: 2 Block 3: 7 Enter the size of the files:- File 1: 1 File 2: 4 OUTPUT File No File Size Block No Block Size Fragment 1 1 2 2 1 2 4 1 5 1 Lab Task: You are required to make changes in the above programs and introduce the use of compaction where required? Write code to simulate Worst-Fit Algorithm?
TASK:
DESCRIPTION
One of the simplest methods for memory allocation is to divide memory into several fixed-sized partitions. Each partition may contain exactly one process. In this multiple-partition method, when a partition is free, a process is selected from the input queue and is loaded into the free partition. When the process terminates, the partition becomes available for another process. The
PROGRAM
FIRST-FIT
#include<stdio.h>
#include<conio.h> #define max 25
void main()
{
int frag[max],b[max],f[max],i,j,nb,nf,temp; static int bf[max],ff[max];
clrscr();
printf("\n\tMemory Management Scheme - First Fit"); printf("\nEnter the number of blocks:"); scanf("%d",&nb);
printf("Enter the number of files:"); scanf("%d",&nf);
printf("\nEnter the size of the blocks:-\n");for(i=1;i<=nb;i++)
{
printf("Block %d:",i); scanf("%d",&b[i]);
}
printf("Enter the size of the files :-\n");for(i=1;i<=nf;i++)
{
printf("File %d:",i); scanf("%d",&f[i]);
}
for(i=1;i<=nf;i++)
{
for(j=1;j<=nb;j++)
{
if(bf[j]!=1)
{
temp=b[j]-f[i];
if(temp>=0)
{
ff[i]=j;
break;
}
}
}
frag[i]=temp;
bf[ff[i]]=1;
}
printf("\nFile_no:\tFile_size :\tBlock_no:\tBlock_size:\tFragement"); for(i=1;i<=nf;i++)
printf("\n%d\t\t%d\t\t%d\t\t%d\t\t%d",i,f[i],ff[i],b[ff[i]],frag[i]);
getch();
}
INPUT
Enter the number of blocks: 3 Enter the number of files: 2
Enter the size of the blocks:-
Block 1: 5
Block 2: 2
Block 3: 7
Enter the size of the files:-
File 1: 1
File 2: 4
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OUTPUT |
|
|
|
|
|
File No |
File Size |
Block No |
Block Size |
Fragment |
|
1 |
1 |
1 |
5 |
4 |
|
2 |
4 |
3 |
7 |
3 |
BEST-FIT
#include<stdio.h>
#include<conio.h> #define max 25
void main()
{
int frag[max],b[max],f[max],i,j,nb,nf,temp,lowest=10000; static int bf[max],ff[max];
clrscr();
printf("\nEnter the number of blocks:"); scanf("%d",&nb);
printf("Enter the number of files:"); scanf("%d",&nf);
printf("\nEnter the size of the blocks:-\n");for(i=1;i<=nb;i++)
printf("Block %d:",i);scanf("%d",&b[i]);
printf("Enter the size of the files :-\n");for(i=1;i<=nf;i++)
{
printf("File %d:",i); scanf("%d",&f[i]);
}
for(i=1;i<=nf;i++)
{
for(j=1;j<=nb;j++)
{
if(bf[j]!=1)
{
temp=b[j]-f[i];if(temp>=0)
if(lowest>temp)
{
ff[i]=j;
lowest=temp;
}
}
}
frag[i]=lowest;
bf[ff[i]]=1;
lowest=10000;
}
printf("\nFile No\tFile Size \tBlock No\tBlock Size\tFragment"); for(i=1;i<=nf && ff[i]!=0;i++)
printf("\n%d\t\t%d\t\t%d\t\t%d\t\t%d",i,f[i],ff[i],b[ff[i]],frag[i]);
getch();
}
INPUT
Enter the number of blocks: 3
Enter the number of files: 2
Enter the size of the blocks:-
Block 1: 5
Block 2: 2
Block 3: 7
Enter the size of the files:-
File 1: 1
File 2: 4
|
OUTPUT |
|
|
|
|
|
File No |
File Size |
Block No |
Block Size |
Fragment |
|
1 |
1 |
2 |
2 |
1 |
|
2 |
4 |
1 |
5 |
1 |
Lab Task:
- You are required to make changes in the above programs and introduce the use of compaction where required?
- Write code to simulate Worst-Fit
Algorithm ?
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