External hard drives are removable or portable hard disks, physically external designed to the computer case, that arebe connected to a computer via USB cables or other meansan external interface such as IEEE1394 andUSB, eSATA, Thunderbolt, or IEEE 1394 (FireWire). They have low cost per gigabyte and are commonly used for backups and the physical transfer oftransferring files between computers.
Hard drives in inclosuresenclosures with network ports are classified asconsidered network attached-attached storage anddevices; questions about these devices should be tagged [nas]nas.