A hard drive enclosure is used to house a hard disk externally, adding storage and flexibility to any system. The enclosure connects to the computer through a universal serial bus (USB) or Firewire port, making it a plug-and-play device. This means it can be turned off and on while the system is up and running. A hard drive enclosure can be used for many purposes and provides portability between desktop and laptop, or home and office.

Security: One of the main advantages to using an external hard drive enclosure is security. Many people are concerned about online threats including viruses, Trojan horses, spyware, hacking, poorly written software and malicious scripts. Some threats can expose data to outside sources, while others corrupt it.

Installing financial data or sensitive programs on an external hard drive is one way to help ensure they stay safe. The hard drive enclosure can be left off when the user isn’t accessing the programs or data, and when online. If several family members share the computer, an external drive is one way to keep key information or software private. Simply remove the hard drive enclosure and lock it in a drawer or safe when not in use.

Back Up: An external hard drive is perfect for storing system back ups or “ghost” images of the main hard disk. If the main drives fails, the ghost image on the external drive can re-create the main disk in mere minutes. Alternately, popular software like Acronis True Image will make a bootable carbon copy of the main disk on the external disk. In this case, the external disk can be removed from the enclosure and installed into the system for an instant fix. It is also possible to boot directly from the hard drive enclosure by using settings in the motherboard’s Basic Input/Output System (BIOS) menu.

Archiving and Libraries: People today are rapidly amassing memory-intensive libraries of music, movie, and graphic files. Storage of these libraries using an external hard drive enclosure frees up on-board system resources for ripping, burning and downloading, while protecting libraries from online threats. Moving these libraries to an external drive also greatly reduces maintenance time for system tasks like file defragmentation, spyware sweeping and virus-checking.

A hard drive enclosure also allows people to reuse “smaller” hard disks that have been replaced by newer, larger capacity drives. For example, as prices have dropped many people have replaced 30, 40 and 60-gigabyte (GB) drives with 250 GB drives or better. Installed in an external hard drive enclosure, older drives become quite useful for archiving.

Portability: It’s simple to transport huge amounts of data between computers using an external hard drive enclosure. Any system equipped with a USB port or Firewire will be able to instantly read the drive and transfer files quickly and easily. An external drive is the next best thing to a massive memory stick.

Alternate Operating Systems (OSs): True geeks might like to use an external hard disk to load a bootable, alternate OS, such as an upcoming Windows OS or Linux. Having a fully functional secondary operating system allows for experimentation without unduly risking the main system, its setup or configuration. One can also try out critical programs for compatibility issues. Installing the OS on an external drive avoids the hassle of creating a dual boot system as is necessary when loading two operating systems on internal disks. Motherboard BIOS settings allow one to easily boot from the external storage device or the internal hard disk.

In considering which hard drive enclosure to purchase, keep in mind that the enclosure must be made for the type of hard drive it will contain. Older drives are IDE, which stands for Integrated Drive Electronics. Newer drives are Serial-ATA or SATA drives. The relevant difference is in the imbedded connector and controller. Noise is also a consideration. Some enclosures have a built-in power supply and fan. Fan design determines whether the fan will be quiet or noisy. If you plan to leave the hard drive enclosure on most of the time, you may want to consider a quieter model. Vendors like NewEgg.com provide customer reviews that can be a great asset in making the right decision.

An external hard drive enclosure is so handy you might want more than one. Once you use it, you’ll likely wonder how you ever got along without its many benefits.