The computer component that holds data is a hard drive and an external hard drive is a hard drive that is outside the computer case in its own enclosure (also called hard drive cage). Every computer needs at least one hard drive to store its operating system, programs and user interpretation. It is usually internal but additional external hard drives have become indispensable.
An external hard drive has become indispensable because there are potential security threats to our computers like virus due to Internet access even after employing anti-virus programs and firewalls.
Apart from this, inadvertent corruption of sensitive documents and additional space required for multimedia storage are some of the problems and one single solution to all such problems is the external hard drive.
The external hard drive is enclosed in an enclosure outside the main computer and is slightly larger than the hard drive itself and sometimes has a cooling fan. The external hard drive is connected to the computer through a high-speed interface cable, which enables the external hard drive to communicate with the computer by means of interfaces like USB and Fire Wire.
An external hard drive is a very constructive piece of equipment in the sense that it allows the user to back up or store important information detached from the main internal hard drive, which could be affected by on-line or off-line activities. An external hard drive can hold sensitive documents, DVD images, disc images, large music files, movies and also a back up of the contents of the main internal hard drive safely and securely. When on line, external hard drive can even be left turned off.
An external hard drive has another advantage – it is portable and operates on plug and play basis. The external hard drive can be used as a storage device for any computer with a USB or Fire Wire capability.
Hard drives are available in two basic formats: SATA (Serial Advanced Technology Attachment) and IDE (Integrated Drive Electronics). IDE drives use a 40-pin connection and are cheaper and SATA hard drives are faster and transfer data at six times the speed of IDE external hard drive.
An external hard drive is basically composed of the Platters, the Spindles and Spindle Motor, the Read/Write Head and the Head Actuator.
The Platters are the actual discs inside the external drive that store the magnetized data. Platters made of glass or ceramic are used because they are thinner and are more heat resistant. Generally, the external hard drives have at least two platters and the larger the storage capacity of the hard drive the more the platters. The Spindle Motor is built right into the Spindle and spins the Platter at a constant set rate ranging from 3600 to 7200 rpm. The Read/Write Head reads and writes the data to the Platter. There is necessarily one head per platter side and each head is attached to a single actuator shaft. Only one of the heads is active at a time reading or writing the data. All the heads are attached to a single head actuator, which moves the head around the Platters. The platters spindle, spindle motor, head actuator and the read or write head are all contained in a chamber called the Hard Disc Assembly (HDA)
We can even buy several hard drives and barter them in and out of the same enclosures, using one for work, one for back up, and one for multi media and song and so on and thus there are boundless reasons to use an external hard drive.