"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. While these work well, they are not the best solution under all circumstances..."