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).
These mantis shrimp average 3-18 cm in length. They have long, narrow bodies, and in addition to their raptorial appendages, a pair of maxillopods, three pairs of legs used for holding prey, three pairs of walking legs, and five pairs of swimmerets, before the body terminates in the telson and paired uropods.