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).
Manta Rays are similar to whale sharks, they are both plankton feeders and are migratory animals. If you join a whaleshark snorkel tour in Cancun then you will be sure to encounter these huge creatures along the way. A giant manta ray can grow up to 9 mts but they tend to be smaller in these waters.