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DATA STORAGE DEVICES - DOC

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					                DATA STORAGE DEVICES
                        A data storage device is a device
                   for recording (storing)information (data).
     A storage device may hold information, process information, or both.
          A device that only holds information is a recording medium.

EXAMPLES:

1.      Multimedia Card

A flash memory card that provides storage for cellphones, PDAs and other handheld
devices. Introduced in 1997 with a 4MB capacity, the 32x24x1.4mm card weighs less
than two grams. By 2005, storage increased to 2GB. The card uses flash memory for
read/write applications or ROM chips (ROM-MMC) for static information, the latter
widely used for adding applications to a Palm PDA.

2.      MultiMediaCards

and SD Memory Cards share the same footprint, but MMCs are thinner and have
only seven pins compared to nine. MMC cards can be read in SD Card readers, but
SD Cards cannot be read in readers designed for MMC only.




Typically, an MMC is used as storage media for a portable device, in a form that can
easily be removed for access by a PC.
3.     USB Drive

Also known as a "flash drive," "pen drive," "keychain drive," "key drive," "USB key,"
"USB stick" and "memory key," numerous brand names have also been coined such
as Lexar's JumpDrive and Trek 2000 International's ThumbDrive.




A flash memory card that plugs into the computer's USB port. Small enough to hook
onto a keychain, it emulates a small disk drive and allows data to be easily transferred
from one machine to another.

4.     XD Picture Card
The xD-Picture Card is a type of flash memory card, used
mainly in digital cameras. xD originally stood for extreme
Digital. The cards were developed by Olympus and Fujifilm
and introduced into the market in July 2002.


5.     SD Memory Card

Secure Digital (SD) is a flash (non-volatile) memory
card format developed by Matsushita, SanDisk and
Toshiba for use in portable devices, including digital
cameras, handheld computers, PDAs and GPS units.
6.      Bubble memory is a type of non-
volatile computer memory that uses a thin film of
a magnetic material to hold small magnetized
areas, known as bubbles, which each store one bit
of data. Bubble memory started out as a promising
technology in the 1970s, but failed commercially
as hard disk prices fell rapidly in the 1980s.




7.     Optical disk,
any of a variety of information storage disks that are
played or read using a laser. Optical disks include
compact discs (CDs and CD-ROMs), laser discs (see
videodisc), and digital versatile discs (or digital video
discs; DVDs and DVD-ROMs).

In computing, sound reproduction, and video, an optical
disc is a flat, circular, usually polycarbonate disc where
data is stored in the form of pits (or bumps) within a flat
surface, usually along a single spiral groove that covers
the entire recorded surface of the disc. This data is
generally accessed when a special material on the disc
(often aluminium) is illuminated with a laser diode.


8.     Floppy disk
A floppy disk is a portable computer storage device that
permits easy handling of data. Commonly used with
personal computers, notebook computers, and word
processors, such disks consist of flat, circular plates made
of metal or plastic and coated with iron oxide. When a disk
is inserted into the disk drive of a computer, information
can be magnetically imprinted on this coating, which will
thereafter permit easy location and retrieval of the same
data.
9.     Magnetic Tape
A sequential storage medium used for data
collection, backup and archiving. Like
videotape, computer tape is made of flexible
plastic with one side coated with a
ferromagnetic material. Tapes were
originally open reels, but were superseded
by cartridges and cassettes of many sizes
and shapes.

				
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