Storage devices and media

Magnetic backing storage media

Fixed hard discs
Used to store operating systems, software and working data.  Any
application which requires very fast access to data for both reading and
writing to.  Not for applications which need portability.  Used for online
and real time processes requiring direct access.  Used in file servers
for computer networks

Portable hard discs
Used to store very large files which need transporting from one
computer to another and price is not an issue.  More expensive than
other forms of removable media

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 ROM
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 eburningf of data, e.g. CDs Z
recording of music downloads from the internet, recording of music
from MP3 format, recording of data for archiving or backup purposes.
DVDs Z 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 3000Z
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