/* Save the changed bitmap file */
FilterOutputStream fos =
new FilterOutputStream
(new FileOutputStream
(profGen.getBmpInPath(diskId)));
bmp.writeTo(fos);
fos.close();
/* Check whether the bitmap is all zero or not.
(All zero means the vmdk does not change at all.) */
profGen.setIsChanged(diskId, bmp.isAllZero() == false);