The movement of the hard drive's read/write heads over different areas of the disk when accessing fragmented files is slower, compared to accessing the entire contents of a non-fragmented file sequentially without moving the read/write heads to seek other fragments.
The giant oceanic manta ray can grow to a disc size of up to 7 m (23 ft) with a weight of about 1,350 kg (2,980 lb) but average size commonly observed is 4.5 m (15 ft). It is dorsoventrally flattened and has large, triangular pectoral fins on either side of the disc.
The reef manta is smaller than the oceanic manta ray, with an average disc-width of 3-3.5 metres (9-11.5ft) and a possible maximum of 4.5 metres (15ft). Itâs likely at such sizes reef mantas would weigh in at around 1.4 tonnes (3,100 lbs). All mantas start off small, so size is not necessarily a good identification feature. The dorsal shading and ventral spot patterning however can be used to discern between these two species.