When purchased new, computers have a limited amount of storage for files and documents. However, there are devices that can increase the amount of storage space that is available. Computer drives and storage devices can provide additional space to store documents, music, video, gaming files and more. These devices can be added to the computer permanently or can be purchased as an external or portable drive. This allows users to transfer files from one computer to another or to back up sensitive files for security purposes.http://www.wisegeek.com/what-is-an-external-hard-drive.htm

Hard drives are the main source of storage for a computer. Each computer is manufactured with a standard hard drive.http://www.pcguide.com/ref/hdd/index.htm External drives can be used to provide an additional amount of storage. These drives are also not permanently attached to the computer, therefore allowing them to transfer information to other computers. External drives also provide a secure back up source to store sensitive information in case of computer malfunction or security threats against the original memory source. By using either a USB or Firewire connection, the drive can be easily connected to any computer and files can be saved onto the drive or shared with the computer. External hard drives are available in a variety of sizes, with some of the largest having a storage capacity of several terabytes.http://www.pcmag.com/article2/0,2817,2358135,00.asp

A flash drive may also be known as a USB drive, thumb drive or a jump drive. These devices are small, portable forms of memory that are commonly used to transfer files from one computer to another. Documents, music files, photos and video can all be loaded onto these drives. Flash drives utilize a USB connection located directly on the storage device to access files and information. http://www.everythingusb.com/flash-drives.htmlWhen using a USB drive, it is important to safely remove the drive from the computer. Removing a storage device improperly can damage the drive and potentially cause the information that is located on it to be lost.