What is a drive enclosure?

Drive enclosures are housings to install hard disk drives separate (HDD) from the computer. These housings may be more or less independent from the computer and options will be reviewed in this article.

Internal enclosures

In the market, there are several drive enclosures meant to be used inside the computer case. Basically, there are two types: Hard drive adapter
They allow for the assembly and fixation of 2.5in drives (the ones used in laptops) as if they were 3.5in ones (standard desktop size). The enclosure typically includes the power and data interface adapting too. Hot-swap enclosures These are used typically in dedicated servers or NAS assemblies. They have two differentiated parts: on one side, a fixed bracket which is mounted in the computer frame (in the same manner as 5.25in CD / DVD drives) and includes electrical and data connection to the computer. On the other side, a removable case will hold the hard drive and includes a handle (and most of the time, a key lock) to remove it from the computer. The use for hot-swap enclosures is multiple: It can be used to make backup copies from several computers (many brackets, one case) or it can be used for quick servicing and repair of computers. It also allows normal users to upgrade computers without having to open the PC housing.

External enclosures

However, the main use of drive enclosure is the external one which can make any (internal) hard drive to be converted to external devices. The market offers multiple choices of these adapters depending on the target drive and planned connection. Target drive
Typically, there are disk enclosures for both 2.5in (laptop HHDs) and 3.5in drives, but also for the (more exotic) 1.8in one. Furthermore, both EIDE and SATA drives can be used. SCSI drives are becoming obsolete and therefore, market availability is quite rare. Planned connection Depending on the available interface in the computer, it will be interesting to have USB (nowadays, the best option will be USB version 3.0 due to higher speeds), FireWire, eSATA etc. In fact, standard USB hard drives are just ready-made assemblies of drive enclosures and normal HDD disks. Special cases for drive enclosures are NAS drives and RAID assemblies which may integrate more than one disk inside. Application is mainly data storage and serving (in first case) or storage protection and optimisation (in case of RAID enclosures). Of course, some NAS systems include several disks in a RAID structure.