Move the hard disk as the name suggests is a hard disk for storage media exchange between computers, large-capacity data storage products that emphasize portability. Market the vast majority of mobile hard drives are standard hard drive, but only a small part of a micro hard drive (1.8 drive, etc.), but the price factor determines the mainstream mobile hard drive or portable hard drive as standard. Because hard disk as the storage medium system, removable hard drive in read/write mode and standard IDE hard disks are the same. Mobile hard drives use USB, IEEE1394, transfer faster interface, high speed transfer data with the system. As of 2009, mainstream 2.5 brand mobile hard drive's reading speed is about 15-25MB/s, write speed of about 8-15MB/s.