Storage devices, the memory banks of the computers have a long lineage of history. The very first storages devices were the punched cards. Punched cards used holes punched in them to store data. It later evolved to gramophone which was used to store music. In gramophone the sound and captured and it is used to vibrate the needle to store the acoustical information to disc. Later Magnetic storage devices came into existence. The data is stored by magnetizing the storage medium. The storage medium varies from magnetic tapes to floppy disk. Floppy disk spawned a new series of storage devices which were once used for installation of operating systems. The above said devices had a slow data recording rate and retrieval rate. The very first breakthrough was optical disks. The data was burned onto a metallic coating. Later the DVD and Blue-ray disks increased the storage capacity with only a few changes to the storing medium to a very range of 50 GB per disk. The above said disks were usually used as backup storage medium.
The most preferred of all is the Hard disk. They replaced everything else that was in use. The size of the hard disk has reduced from 10” to tiny dimension of 1”, whereas the capacity hasn’t decrease rather the opposite. Hard disks are now capable of storing upto 2TB of data which was once a dream. Finally a hint to people who are buying a new rig, don’t go for high end hard disk unless you’re a gamer. Look of a hard disk which has more cache memory (32 MB preferred). The drawback of hard disks is the moving parts inside the disk. They are more prone to failure. With the dawn of Solid State Drive (SSD) the storage devices will again have new king reigning for a long time. If you want to buy a hard disk this the right time the prices have fallen very much. Search for online buying sites at dmoz.org and read more about hard disks in the all time open source Wikipedia.