Complex sentence: Traditional longitudal storage hard disks store bits longitudally, that is, parallel to the surface of the hard drive, which means that the north and south poles of the grains of the magnetic medium are oriented parallel to the platter surface.
Split into simpler sentences: Traditional longitudal storage hard disks store bits longitudally, that is, parallel to the surface of the hard drive. This means that the north and south poles of the grains of the magnetic medium are oriented parallel to the platter surface.