A isk enclosure is essentially a specialized chassis designed to hold and power disk drives while providing a mechanism to allow them to communicate to one or more separate computers. Drive enclosures provide power to the drives therein and convert the data sent across their native data bus into a format usable by an external connection on the computers to which it is connected. In some cases, the conversion is as trivial as carrying a signal between different connector types. In others, it is so complicated as to require a separate embedded system to retransmit data over connector and signal of a different standard. Factory-assembled external hard disk drives, external DVD-ROM drives, and others are all built around disk enclosures. Bulkier models built around 2.5" & 3.5" hard drives and full-height 5.25" DVD-ROM drives use enclosures that are often nearly identical to OEM enclosures.