IGCSE Syllabus Section 3

Section 3: Storage devices and media
Candidates should be able to:
(a) describe common backing storage media (including magnetic tapes, hard discs, all forms of CD and
DVD, memory sticks, flash memory) and their associated devices
(b) identify typical uses of the storage media, including types of access (e.g. serial/sequential, direct/
random) and access speeds
Media Use
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

4. Curriculum content
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 ‘‘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
Candidates should be able to:
(c) describe the comparative advantages and disadvantages of using different backing storage media
(d) define the term backup and describe the need for taking backups
(e) describe the difference between main/internal memory and backing storage, stating the relative benefits
of each in terms of speed and permanence