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 dorsal fins are small and at the base of the tail. The largest mantas can reach 1,350 kg (2,980 lb). In both species the width is approximately 2.2 times the length of the body; M. birostris reaches at least 7 m (23 ft) in width while M. alfredi reaches about 5.5 m (18 ft).
All the Betta species are small fishes, but they vary considerably in size, ranging from under 2.5 cm (1 in) total length in B. chanoides to 12.5 cm (5 in) in the Akar betta (B. akarensis). Bettas are anabantoids, which means they can breathe atmospheric air using a unique organ called the labyrinth.