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).
This famous photo shows a model of an oceanic manta ray that was caught off the coast of New Jersey in 1933. Although the animal here is a model, it is true to the real mantaâs size â it measured six metres from wing-tip-to-tip and weighed over 5,000 pounds.