Data storage device
Recording can be done using virtually any form of energy. 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.
Electronic data storage is storage that requires electrical power to
store and retrieve data. Most storage devices that do not require visual
optics to read data fall into this category. Electronic data may be
stored in either an analog or digital signal format. This type of data
is considered to be electronically encoded data, whether or not it is
electronically stored. Most electronic data storage media is considered
permanent (non-volatile) storage, that is, the data will remain stored
when power is removed from the device. In contrast, electronically
stored information is considered volatile memory
With the exception of 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 (e.g. hands, mouths, musical instruments) and devices
that are intermediate in the storing/retrieving process (e.g. eyes,
ears, cameras, scanners, microphones, speakers, monitors, projectors)
are not usually considered storage devices. Devices that are exclusively
for recording (e.g. printers), exclusively for reading (e.g. barcode
readers), or devices that process only one form of information (e.g.
phonographs) may or may not be considered storage devices. In computing
these are known as input/output devices.
An organic brain may or may not be considered a data storage device.[1]
All information is data. However, not all data is information.
Data storage equipment
The equipment that
accesses (reads and writes) storage information are often called storage
devices. Data storage equipment uses either:
portable methods (easily replaced),
semi-portable methods requiring mechanical disassembly tools and/or opening a chassis, or
inseparable methods meaning loss of memory if disconnected from the unit.
The following are examples of those methods:
Portable methodsHand crafting
Flat surface
Printmaking
Photographic
Fabrication
Automated assembly
Textile
Molding (process)
Solid freeform fabrication
Cylindrical accessing
Card reader/drive
Tape drive
Mono reel or reel-to-reel
Cassette player/recorder
Disk accessing
Disk drive
Disk enclosure
Cartridge accessing/connecting (tape/disk/circuitry)
Peripheral networking
Semi-portable methods
Hard drive
Circuitry with non-volatile RAM
Inseparable methods
Circuitry with volatile RAM
Chemical synapse
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.
Ancient and timeless examples
Optical
Any object visible to the eye, used to mark a location such as a, stone, flag or skull.
Any crafting material used to form shapes such as clay, wood, metal, glass, wax.
Quipu
Any branding surface that would scar under intense heat.
Any marking substance such as paint, ink or chalk.
Any surface that would hold a marking substance such as, papyrus, paper, skin.
Chemical
DNA
Pheromone
Modern examples by energy used
Graffiti on a public wall. Public surfaces are being used as unconventional data storage media, often without permission.
Photographic film is a photochemical data storage medium
A floppy disk is a magnetic data storage medium
Hitachi 2.5 inch laptop hard drive. A hard drive is both storage equipment and a storage medium
Four major types of memory cards (from left to right: CompactFlash, MemoryStick, Secure Digital, and xD.
Picture of a Holographic Versatile Disc by Optware.Chemical
Dipstick
Thermodynamic
Thermometer
Photochemical
Photographic film
Mechanical
Pins and holes
Punch card
Paper tape
Piano roll
Music box cylinder or disk
Grooves (See also Audio Data)
Phonograph cylinder
Gramophone record
DictaBelt (groove on plastic belt)
Capacitance Electronic Disc
Magnetic storage
Wire recording (stainless steel wire)
Magnetic tape
Floppy disk
Optical storage
Photo paper
Hologram
Projected transparency
Laserdisc
Magneto-optical disc
Compact disc
Holographic versatile disc
Electrical
Semiconductor used in volatile RAM microchips
Floating gate transistor used in non-volatile memory cards
Modern examples by shape
A typical way to
classify data storage media is to consider its shape and type of
movement (or non-movement) relative to the read/write device(s) of the
storage apparatus as listed:
Paper card storage
Punched card (mechanical)
Tape storage (long, thin, flexible, linearly moving bands)
Paper tape (mechanical)
Magnetic tape (a tape passing one or more read/write/erase heads)
Disk storage (flat, round, rotating object)
Gramophone record (used for distributing some 1980s home computer programs) (mechanical)
Floppy disk, ZIP disk (removable) (magnetic)
Holographic
Optical disc such as CD-ROM, CD-R, CD-RW, DVD, DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-RAM, Blu-ray, Minidisc
Hard disk (magnetic)
Magnetic bubble memory
Flash memory/memory card (solid state semiconductor memory)
xD-Picture Card
MMC
USB Keydrive (also known as a "thumb drive")
SmartMedia
CompactFlash I and II
Secure Digital
SONY Memory stick (Std/Duo/Pro/MagicGate versions)
Solid state disk
Bekenstein (2003) foresees that miniaturization might lead to the invention of devices that store bits on a single atom.