There are three general classifications or categories of external hard drives which cater to specific needs and offer distinct and useful features.
USB Hard Drives. The most common and portable hard drives used for back up today are the USB flash drives or dongles. They are cheap, readily available and sold elsewhere, and can contain larger amounts of data compared to CDs, DVDs, and its diskette predecessors. But on the negative side, they are more susceptible to damage, virus and malware attacks especially if they are to be used from one computer or port to another. Its data capacity is also limited compared to the heavy duty FireWire and eSATA drives.
FireWire Drives. A FireWire, the best external hard drive is categorized in between the USB and eSATA drives. Its main feature is the speed of data transfer rate when this drive is used which is perfect for individuals who love playing and copying media files and contents. But unlike eSATA drives capacities of FireWire drives is also limited or lower, and has no spinning disk and other functionalities common to heavy duty hard drives.
eSATA Drives. The eSATA drive are another common external hard drives used by most individuals today. Within every eSATA drive, a powerful hard disk drive similar to those used in laptops and computers is enclosed. When it comes to storage capacity, they range from 80, 160, 250, 320, 500 gigabytes and even up to the terabyte range. They are also much faster and perform similarly to internal hard disk drives.
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