|
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 data. Electronic data storage requires electrical power to store and retrieve that data. Most storage devices that do not require vision and a brain to read data fall into this category. Electromagnetic data may be stored in either an analog data or digital data format on a variety of media. This type of data is considered to be electronically encoded data, whether it is electronically stored in a semiconductor device, for it is certain that a semiconductor device was used to record it on its medium. Most electronically processed data storage media (including some forms of computer data storage) are considered permanent (non-volatile) storage, that is, the data will remain stored when power is removed from the device. In contrast, most electronically stored information within most types of semiconductor (computer chips) microcircuits are volatile memory, for it vanishes if power is removed. Except for barcodes and OCR data, electronic data storage is easier to revise and may be more cost effective than alternative methods due to smaller physical space requirements and the ease of replacing (rewriting) data on the same medium. However, the durability of methods such as printed data is still superior to that of most electronic storage media. The durability limitations may be overcome with the ease of duplicating (backing-up) electronic data. ==Terminology== Devices that are not used exclusively for recording such as hands, mouths, musical instruments, and devices that are intermediate the storing/retrieving process, like eyes, ears, cameras, scanners, microphones, speakers, monitors, or video projectors, are generally not considered storage devices. Devices that are exclusively for recording such as printers, exclusively for reading, like barcode readers, or devices that process only one form of information, like phonographs may or may not be considered storage devices. In computing these are known as input/output devices. All information is data. However, not all data is information. Many data storage devices are also media players. Any device that can store and playback multimedia may also be considered a media player such as in the case with the HD media player. Designated hard drives are used to play saved or streaming media on home cinemas or home theater PCs. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Data storage device」の詳細全文を読む スポンサード リンク
|