C / C++ / MFC

drive_handle=Createfile(L"\\\\.\\PhysicalDrive0",......);

for(  i=0;total_noof_clusters;i++)//assign 0 as logical startling offset.
{
// convert cluster logical offset to physical offset
// (source& dest same size,same file system)

 phys_offset_source= conversion(i);  // this value I get correctly
 phys_offset_dest= conversion(i);  // this value I get correctly


 DWORD dwPtr1=SetFilePointer(drive_handle,phys_offset_source,NULL,0);
 if (dwPtr1 == INVALID_SET_FILE_POINTER) // Test for failure
 {
 printf("\nSetFilePointer Failed to read from source,:%d\n",GetLastError());
 return 0;
 }


 if(!ReadFile(drive_handle,
                    bBuffer1,
                    cluster_size,
                    &dwRetBytes1,
                    0))
{
printf("\nUnable to Read the Disk Error: %d\n",GetLastError());   
return o;
}
   
 DWORD dwPtr2=SetFilePointer(drive_handle,phys_offset_dest,NULL,0);

 if (dwPtr2 == INVALID_SET_FILE_POINTER) // Test for failure
 {
 printf("\nSetFilePointer Failed to write position%d\n",GetLastError());
 return 0;
 }


 if(!WriteFile(drive_handle,
                    bBuffer1,
                    cluster_size,
                    &dwRetBytes1,
                    0))
{
printf("\nUnable to write he Drive Error: %d\n",GetLastError());   
return o;
}

} // next cluster