The idea of external hard disk came into application these days. The immense storage capacity and the relative speed of USB Pen Drive gave way to the idea of using an external hard drive to complement the storage and performance capacity of the in-built platter-based hard disks. The idea was good, and this inexpensive device came into wide application. The most striking feature was the speed, when the external hard disks used interfaces faster than the conventional 2.0 interface. Many times, it excels NAND based flash memory by providing data sustained at much higher rate.
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However, these devices too had many drawbacks. The major draw back was the weight and size of the drive, obviously higher than that of USB Flash Memory. However as far as weight per unit of stored data is considered, it is much lesser than that of a flash drive. Furthermore, since it is not the static memory that is being used, the hard disk is easily prone to damage. A slight fall, vibration or any shock of the sort can cause severe damage to the disk. Also, the data is susceptible to magnetic field regardless of being encased in a protective cover. Thus, according to this viewpoint, it seems to outshine flash drives, despite of some demerits.
