There are four types of external interfaces for mobile hard drives: parallel interface, USB interface, IEEE1394 interface, and SATA interface, and most of their built-in interfaces are IDE interfaces, which are used in conjunction with IDE-interface hard disks.

The four types of interfaces have the following characteristics:

1, parallel interface (i.e., ATA interface) hard disk enclosure is the earliest hard disk enclosure, through the computer's parallel interface with the computer connection, which is characterized by the transfer speed is relatively fast, inexpensive, the shortcomings of the installation is inconvenient to use, the need for independent switching of the power supply;

2, the USB interface of the mobile Hard disk box is the current mainstream, its biggest advantage is easy to use, support for hot-swap and plug-and-play;

3, IEEE1394 interface, also known as Frie wire interface (commonly known as "FireWire" in Chinese), high data transfer rate, IEEE1394a interface can provide 100Mbps, 200Mbps, 400Mbps, 200Mbps, 400Mbps, 200Mbps, 400Mbps, 200Mbps, 400Mbps, 200Mbps, 400Mbps, 200Mbps, 400Mbps. 200Mbps, 400Mbps and other transmission formats; IEEE1394b can provide 800 Mbps data transfer rate. IEEE1394 was originally Apple's computer above the interface, in the ordinary desktop is relatively rare;

4, SATA interface using embedded clock signals, with a stronger error correction capability, compared with the previous its biggest difference The biggest difference is the ability to check transmission commands (not just data), and if errors are found, they are automatically corrected, which greatly improves the reliability of data transmission.

Mobile Hard disk (Mobile Hard disk) as the name suggests is a hard disk as a storage medium, the exchange of high-capacity data between computers, emphasizing the portability of the storage products. The vast majority of mobile hard disks on the market are based on standard hard disks, while only a small portion are based on micro hard disks (1.8-inch hard disks, etc.), but the price factor dictates that mainstream mobile hard disks are still based on standard notebook hard disks.

Because of the use of hard disk as a storage medium, so the mobile hard disk in the data read and write mode and the standard IDE hard disk is the same. Mobile hard disk is mostly used USB, IEEE1394 and other transmission speed faster interface, can be higher speed and system for data transmission. As of 2009, the read speed of mainstream 2.5-inch brand mobile hard disk is about 15-25MB/s, and the write speed is about 8-15MB/s.