When and Why to Use an External Hard Drive
by: Sal Cangeloso
When you need to back up or store data there are many options on where to put it. The back up can be placed on your local system, on a network-attached storage (NAS) device, on a remote system/file server on the network, a remote storage service, tape, optical disks, and or a number of other places. The method which has gained favor with consumers though, is the external hard drive.
Though external hard drives come in many different flavors, they are all essentially an internal 3.5" or 2.5" hard drive which has been placed in an enclosure. This enclosure protects the drive from the elements, powers it, and gives it a way to connect to a computer. Most, but not all, external hard drive enclosures provide some sort of cooling.
External hard drives can either be purchased as a pre-packaged kit, with the drive, enclosure, and sometimes software, or as separate components. An example of a external kit product is Maxtor's OneTouch. If you already have a spare hard drive it makes sense to buy an enclosure for that. These normally cost from $20-$40 depending on on how nice the design and materials are and its connectivity.
There are a number of different ways which the enclosure can connect with your computer. By far the most popular of these is USB2.0, a connection which practically every computer has and one which is hot-pluggable. Another option which had been losing favor is FireWire, this has good transfer speeds but not nearly as many computers use it. Some newer models use a serial ATA connection which means cable routing is a little tougher but there will be greatly improved transfer speeds. The upside of SATA, aside from the speed, is that these external drives are bootable, the downside is that they are not hot-pluggable. These normally come with a pass-through card so that the drive can connect to the motherboard's SATA connections and no PCI adapter card is needed.