Section 3: Magnetic backing storage media

Question 1

Hard Drives (Magnetic)

Answer 1

Very large storage capacity ( 1Tb)
Random access devices and can be used to store all types of films and movies
Data access speeds are very fast.
Transport data from one computer to another

Question 2

Fixed Hard Drive(Magnetic)

Answer 2

Store operating systems, software and working data.
Used for applications which need fast access to data for reading, writing
Not for applications which need portability.
Online and real time processes requiring direct access. Used in file servers for computer networks

Question 3

Magnetic tapes(Magnetic)

Answer 3

Used for applications which require 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 batch processing applications i.e: Bank cheques, payroll processing, stock control/

Question 4

CDs and DVDs in general (Optical)

Answer 4

CDs tend to be used for large files (but smaller than 1Gb) to hold such as music and general animation.
DVDs are used to hold very large files (several Gb) such as films.
Portable
Can be used to store computer data

Question 5

CD ROM/DVD ROM(Optical)

Answer 5

Applications which require the prevention of deletion of data
CDs used by:
+ software companies for distributing software programs and data
+ music companies for distributing music album
+ book publishers for distributing reference books
DVDs used by film distributors.

Question 6

CD R/DVD R(Optical)

Answer 6

Applications which require a single ‘burning’ of data
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

Question 7

CD RW/DVD RW(Optical)

Answer 7

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

Question 8

DVD RAM(Optical)

Answer 8

Same properties as DVD RW
Quicker access and data
Can be overwritten more easily
Similar to floppies but has  3000-6000 times more storage 
Uses optical technology

Question 9

Blu-ray(Optical)

Answer 9

Capacities of 25Gb, 50Gb and 100 Gb.
Used for storing films (movies)
25Gb equates to 2 hrs HDTV, 13hrs standard definition TV.
Can playback video on a disc while simultaneously recording HD video

Question 10

Solid state backing storage ( in general )

Answer 10

Smallest form of memory, used as removable storage. More robust than other forms of storage.
More expensive than other forms
Can be easily written to and updated

Question 11

Memory sticks/Pen drives

Answer 11

Can store up to many Gb. Used to transport files and backup data from computer to computer.

Question 12

Flash memory cards

Answer 12

Used in digital cameras, palmtops, mobile phones, MP3 players

Question 13

Type of access?

Answer 13

Serial / Sequential Access

Direct / Random Access

Question 14

What is meant by serial access?

Answer 14

A serial (or sequential) access storage device is one that stores files one-by-one in a sequence.
Only accessible in the same order that you recorded them.
Systems that store things on tape (video, music, computer data, etc.) are always serial access

Question 15

What is meant by random access?

Answer 15

A direct (or ‘random’) access storage device is one that stores files so that they can be instantly accessed - there is no need to search through other files to get to the one you want.
eg DVD

Question 16

What is the order of Storage media by capacity(least to greatest) and speed(slowest to fastest)?

Answer 16

Floppy disc 1.44Mb
Zip disc 750Mb 
Cd-ROM 800Mb
Jazz Drive 2Gb
DVD 4.7 gb
USB memory stick 16Gb 
Backup tape 800Gb
Hard drive 1Tb