How storage devices works


Data Storage Media A Guide to Selecting Media For Storing and Backing Up Computer Data

Data, or information stored on your computer,Ideal  for
can either be held on fixed disk drives
inside the computer or on removable mediaTransferring  files
such as CD's that can be inserted and
removed. Removable media can be used toHolding  temporary  data
transfer files between computers or to backup
the data already existing on fixed diskNot  so  good  for
drives. There are three types of removable
media:  Magnetic,  Optical  and  Flash.Holding important permanent files-in case
they  are  accidentally  deleted
Magnetic  Storage
Double  Density  CD  (DDCD)
Magnetic Storage: Hard disks, floppy disks
and digital audiotape are examples ofThis disc has a much greater storage capacity
Magnetic storage. They operate through a readthan  an  average  CD-R  or  CD-RW.
write head, which creates and reads magnetic
impressions  on  the  disk.Ideal  for
The  downsideBacking  up
The magnetic impression only lasts for aroundStoring  archival  data
five  years
Enhanced  CD
The capacity of most removable magnetic disks
is  too  low  for  many  types  of  filesEnhanced CD (E-CD) is an audio CD with CD-ROM
data added. CD-ROM data is added in the space
Optical  storagenot taken by audio. Recording artists can use
this to include videos, lyrics, interviews or
Optical Storage holds information in digitalpromo material. The E-CD can be played on a
form that is written and read by a laser. AllCD player but to view additional material you
CD  and  DVD  devices  are  examples of this.need access to a multimedia-capable device,
such as a CD-i player, DVD-ROM, or CD-ROM
The  upsidedrive.
Increased capacity: one Optical disc canBridge  Disks
store the same amount of data as over 500
diskettesA CD-Bridge disc holds extra information on a
CD-ROM XA track. The disc can be played on
Durability: they last up to seven times aseither a CD-i player attached to a
long  as  Magnetic  forms  of  storagetelevision, or a CD-ROM XA drive attached to
a computer. Software such as Photo or a
Flash  Memory (Solid-State Removable Storage)Karaoke CD player can provide lots of fun
with  the  Bridge  Disk.
Solid-state memory (or Flash memory) is a
high-performance plug-and-play storage deviceDVD (Digital Versatile Disk): More than
that contains no moving parts. It is found inmovies
digital cameras, video game consoles and
digital audio players. You can use it in theAlthough DVD's have become more associated
form of USB Flash Drives to transfer orwith video, they can also hold audio and
backup data. Flash memory is small, light andcomputer data; hence their name Digital
fast.Versatile Disk. Like the CD, a DVD is a
120-mm by 1.2mm thick disk. However the DVD
Backuphas more tracks than a CD so holds far more
data. CD's have an unvarying storage capacity
Backup is the copying of files onto portableof  750MB,  whereas  DVD's  store up to 17GB.
media so that if your computer crashes, data
wont be lost in oblivion. Backup is usuallyA range of acronyms is also used to
routine in large businesses but is oftendistinguish between the different types and
neglected by individual users. Some suggestcapabilities of DVD's available. These
backing up data files and duplicating yourinclude DVD-ROM, DVD-R, DVD-RW, DVD+RW and
hard drive weekly. It takes around 45 minutesDVD-Audio.
to  backup  a  500-megabyte  hard  disk.
DVD-ROM
There are two options- Local or Internet
backup. The following is a list of LocalDVD-ROM (Digital Versatile Disc - Read Only
backup options. Most of these also double asMemory) is similar to a movie DVD, but is
devices used to transfer data betweendesigned for computers. The DVD-ROM stores
computers.data in the same way that the CD-ROM does and
is  used  in  the  DVD-ROM  drive of your PC.
Diskettes
The  upside
Zip  Drives
Larger storage space hold more data than a
CD'sCD
DVD'sCan be filled with nearly everything; video,
music  or  computer  specific  data
Flash  Drive
A  base  speed  of  1.32  megabytes/sec
Internet  Backup
The  downside
Another backup option is sending your files
to an Internet site for safekeeping. If yourMany older computers do not have a DVD-Rom
computer crashes you can simply download themdrive  installed
from the site. Here are a few examples of
such  sites:Can  be  recorded  on  only  once
Backup  Defender-DVD-Audio
My  Backup-DVD-Audio (DVD-A) is designed for audio data
and high-quality music. Its storage capacity
N.B. The author does not recommend or endorseis seven times that of a CD and provides at
any  of  the  above  service  providers.least twice the sound quality. Like the
Enhanced CD, DVD-A can contain other data,
Diskettes  and  Zip  Drivesproviding the listener with extra information
such as lyrics or images. DVD-A is predicted
Disketteby many to replace the standard audio CD in
the  music  industry.
A Diskette is a 3.5-inch removable magnetic
disk. The older version, the floppy disk, isDVD-R
5.25 inches square and flexible. Copying to a
diskette  is  quick  and  economical.Like the CD-R, the DVD-R (Digital Versatile
Disc-Recordable)  can  be  recorded  on once.
Ideal  for
The  upside
Those who use their PC for personal finance -
the diskette enables you to retrieveA DVD-R can contain an assortment of
checkbook  balances  etc.information; video, text, audio and computer
data
Projects that need to be continuously backed
up such as a film script, as it is a cheapA DVD-R can be played on your normal DVD
alternative.video player but remember, if you have
additional data not of the same format e.g.
Not  so  good  forvideo and audio together, you will need a
DVD-ROM  or  Multimedia  player  of some kind
Some newer computer and laptop models that do
not have a diskette or floppy driveA DVD-R is read at the same speed as
installed.commercially  made  DVD's
Large amounts of data as diskettes dont haveDVD-RW  and  DVD+RW
a  great  storage  capacity
Similar to the CD-RW, a DVD-RW or DVD+RW
Zip  Drives(Digital Versatile Disc Rewritable) can be
recorded on, rewritten and erased multiple
A Zip drive is a small, square shapedtimes. Other than this they are identical to
magnetic disk that is ideal for backing upthe  DVD-R.
your PC. The 100-megabyte size holds the
equivalent of 70 floppy diskettes. They alsoDVD minus and plus are just different
come  in  a  250-megabyte  sizeversions  with  the  same  functionality.
Ideal  forThe  Future  of  CD/DVD  Storage
Duplicating  your  entire  disc  driveThe majority of the technology industry
predicts that soon DVDs, with their larger
Archivingstorage capacity and faster access time, will
replace CDs. DVD-ROM drives are likely to be
Storing  graphic  images or other large filessold with new computer systems in the way
that CD-ROM drives once were. However we are
Transferring  large  filesalways on the cusp of newer technologies,
such  as  the  HD-ROM.
Keeping certain data separate from files on
your  hard  diskHD-ROM  (High  Density-Read  Only  Memory)
The  downsideHD-ROM uses a more precise particle beam to
write data. This enables information to be
They seem to be a fleeting technology - mostwritten on more durable materials such as
computers do not have a Zip Disc drivemetal so storage is virtually permanent.
installed and opinion varies on how long theyHD-ROM has hundreds of times the storage
will  be  around  for.capacity  of  the  CD-ROM.
Compact  DisksFlash  Drives
There are different standards of CD's thatA Flash drive is a small portable memory
have different capabilities. Just to confusestick that holds anywhere from 1Mb to 1GB of
us they are recognized by seemingly similardata. It is surprisingly lightweight and is
acronyms;  CD-R, CD-RW, CD+RW, DDCD and E-CD.often worn around the neck or carried as a
funky key chain. They are compatible with any
CD-RPC that has USB port and with Mac OS 9 and OS
X,  Windows  2000  and  XP  or  Linux 2.4.17.
CD-R (Compact Disc - Recordable) is a CD that
can be recorded to only once. It usuallyThe  upside
holds 74 minutes of audio or 650 MB of data,
although newer versions hold up to 80 minutesDurable  -  more  so  than  CD's  or  DVD's
of audio (700 MB of data). If your PC has CD
burning software and a compatible CD-R orNo need for batteries or a separate power
CD-RW drive, the CD-R can be used in the samesource
way as a diskette. However unlike a diskette
it cannot be deleted or overwritten. Look outConvenient - your computer should recognize
for CD-Rs that have an additional protectivethe additional drive as soon as you insert it
layer which make them less susceptible tointo  the  USB  port
damage  caused  through  scratching.
Ideal  for  backup
Ideal  for
Larger storage capacity then many other
Making  music  CD'sportable  devices
Storing  photosMore portable than ZIP drives, CD's and
Diskettes
Storing  permanent  data
Quick  transfer  rate  (approx.  1Mb/sec)
Not  so  good  for
Edit, rewrite, delete as many times as
Transferring files as they can only be useddesired
once
Help desk personnel can use Flash Drives as a
CD-RW/CD+RWportable toolkit that includes system updates
and  recovery  tools.
A CD-RW (Compact Disc Rewritable) and CD+RW
can be recorded onto as many times asThe  downside
desired. Data can be overwritten and erased.
Other than this, the CD-RW is identical toMore  expensive  than  other portable devices
the CD-R. If it wasn't for their finite
durability CD-RWs and CD+RWs could be reusedViruses - The portability and compatibility
endlessly.of the Flash Drive increases the chance of
spreading viruses.



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