# 4 COMPUTER STORAGE

EXTERNAL HARD DISKS / DIRECT ATTACHED STORAGE (DAS)

A hard drive is a computer component that holds data. Every computer needs at least one hard drive to store its operating system, programs and user information. This drive usually is internal, or built into the computer, but as computer systems have evolved and different needs, threats and circumstances have arisen, external hard drives have become more popular. External hard drives usually are used in addition to internal hard drives in order to store more data. They also allow the user to put sensitive, confidential or otherwise important information on them, then disconnect them and store them in secure locations.

Physical Characteristics

An external hard drive sits outside the main computer tower in its own enclosure. This portable encasement is slightly larger than the hard drive itself, and it sometimes contains a cooling fan. The external hard drive is connected to the computer via an interface cable, which allows the external hard drive to communicate with the computer so that data can be passed back and forth.

Why It is Needed

Internet access regularly exposes computers to potential security threats such as Trojan horses, viruses and spyware. It has become increasingly difficult to guard against these threats, even when employing firewalls and antivirus programs. Aside from online threats, multiple family members often use the same system, putting sensitive documents at higher risk of inadvertent corruption or loss. Additionally, the space required for multimedia storage has soared, with digital media files often taking up large amounts of space on a user's hard drive. All of these concerns can be addressed with an external hard drive.

Advantages

A portable or external hard drive allows the user to back up or store important information separate from the main internal hard drive, which could become compromised, damaged or corrupted. Sensitive documents, large music files, movies, images and other backup files can be kept securely and safely on an external hard drive. Another advantage of an external hard drive is that it is portable and operates on a plug-and-play basis so that other compatible computers can recognize the drive as a storage device and can be used to access the files. A user can easily transfer files from the computer to the portable hard drive or from the portable drive to the computer, or programs can be run directly from the portable hard drive.

source : wisegeek