Thursday, March 10, 2011

Storage Devices and Media

Fixed Hard Disks: Used to store operating systems,software and working data.

Portable Hard Disks: Used to store very large files which need transport from one computer to another.

Magnetic Tapes: Any application which requires extremely large storage capacity and speed of access is not an issue. Uses serial access for reading and writing.  Used for backups of file servers for computer networks.  Used in a variety of batch processing applications such as reading of bank cheques, payroll processing and general stock control.


Optical backing storage media such as CDs and DVDs: CDs tend to be used for large files (but smaller than 1Gb) which are too big for a floppy disc to hold such as music and general animation.  
DVDs are used to hold very large files (several Gb) such as films.  Both 
CDs and DVDs are portable i.e. they can be transported from one 
computer to another.  Both can be used to store computer data 


CD ROM/DVD ROM0: Applications which require the prevention of deletion of data, 
accidental or otherwise.  CDs used by software companies for 
distributing software programs and data; by music companies for 
distributing music albums and by book publishers for distributing 
encyclopaedias, reference books etc.  DVDs used by film distributors 


CD R/DVD R Applications which require a single ‘‘burning’’ of data, e.g. CDs –– 
recording of music downloads from the internet, recording of music 
from MP3 format, recording of data for archiving or backup purposes.  
DVDs –– recording of films and television programs 


CD RW/DVD RW Applications which require the updating of information and ability to 
record over old data.  Not suitable for music recording but is very 
useful for keeping generations of files.  DVDs have between five and 
ten times the capacity of CDs 


DVD RAM Same properties as DVD RW but quicker access and data can be 
overwritten more easily.  Similar to floppies in nature but has 3000–– 
6000 times more storage and uses optical technology 


Blu-ray: Capacities of 25Gb, 50Gb and 100 Gb.  Used for storing films (movies). 
25Gb equates to 2 hrs HDTV, 13hrs standard definition TV.  It is 
possible to playback video on a disc while simultaneously recording HD 
video.  (Will be) used for storage of PC data 


Solid state backing storage: Smallest form of memory, used as removable storage.  More robust 
than other forms of storage.  More expensive than other forms, but 
can be easily written to and updated 


Memory sticks/Pen drives: Can store up to many Gb.  Used to transport files and backup data 
from computer to computer 


Flash memory cards: Used in digital cameras, palmtops, mobile phones, MP3 players 

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