Data storage device

A data storage device is a device for recording (storing) information (data). Recording can be done using virtually any form of energy, spanning from manual muscle power in handwriting, to acoustic vibrations in phonographic recording, to electromagnetic energy modulating magnetic tape and optical discs.
A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store and retrieve information

Recording medium

A recording medium is a physical material that holds data expressed in any of the existing recording formats. With electronic media, the data and the recording medium is sometimes referred to as "software" despite the more common use of the word to describe computer software. With (traditional art) static media, art materials such as crayons may be considered both equipment and medium as the wax, charcoal or chalk material from the equipment becomes part of the surface of the medium.

Weight and volume

Especially for carrying around data, the weight and volume per MB are relevant. They are quite large for written and printed paper compared with modern electronic media. On the other hand, written and printer paper do not require (the weight and volume of) reading equipment, and handwritten edits only require simple writing equipment, such as a pen.

Hard Drives

A hard drive operates like a group of record players stacked on top of each other. Several platters spin on a common spindle, and an arm moves to place read/write devices–the heads, analogous to turntable cartridges–over specific parts of each platter to read or change polarities of portions (sectors) of the platter.
The platter is typically made of glass or a non-magnetic alloy, coated with a thin layer of a ferromagnetic material. The platter is spun at very high speeds (up to 10,000 rpm), and the common arm moves to give the heads access to almost every part of the platter.Unfortunately, the mechanical nature of hard drives makes them prone to failure, and data loss is not uncommon.

Tape Drives

Like a hard drive, positive and negative charges are written to a magnetized medium. In a digital ape, that medium is a half-inch wide magnetized ribbon. Blocks of data are stored in contiguous regions on the tape, but finding the desired region to read data back can take a lot of winding. Tape drives wind backward and forward automatically to find the requested data, but wait times can still be upward of 60 seconds. Modern tape drives can deliver 80 megabytes per second once transfer begins

Hard drive storage is quite different from magnetic tape, though both of them are usually used for backup solutions. Both technologies operate on the same basic principles, which have been in use for over 60 years. The benefits and pitfalls of each make them best suited to different situations