Backing up of data IGCSE ICT Chapter 3.ppt

IGCSE Chapter 3

1. 3.
Storage
devices and
media
By:Teena Sharma

2. Starter:
Identify the
devices

3. Objectives
Define what is backing up of data?
Explain why back up data?

4. Introduction
Definition: "Data Storage is where we put
data in a ‘known’ place (Save) which we
can come back to later and get the data
back again (Read)"
Data Storage (what is it?)

5. Introduction
There are some terms that you need to be
aware of when we talk about data storage:
Writing of data = Storing data (also known as
saving)
Reading data = Getting our data back (also
known as opening)
Overview of Data Storage:

6. Data can either be stored
temporary or permanent.
RAM (computer memory) is used to
store data temporarily
Backing Storage Devices are used to
store data permanently.

7. Activity 1
Give answers
1.RAM stores data……………(permanently/
Temporary)
2.Writing of data means…………..
3.Reading of data means ………….
4.Data Storage is where we put data in a ‘known’
place (Save) which we can come back to later
and get the data back again (Read)"

8. Objective
Explain why back up data?

9. 3.1.1 what is
backing up
of data?
3.1 Backing up Of Data
WHAT?
Refers to the copying of files/data to a different
medium in case of a problem with the main
secondary storage deivce

11. There are many ways we can lose computer files. We could accidentally delete
them, files could be infected with a virus or someone could even deliberately
erase our files!
Backing up is considered 'good practice' and helps prevent us
from losing our work and files.

12. 3.1.2 why
back up
data?
WHY?
To safeguard against loss of data due to failure of
the original secondary storage device
To safeguard against damage from hackers
Made in case the files need to be used elsewhere

13. There are many reasons why backups are made. Some of the common
reasons are
summarised below:
Why Backup Data?

14. Backups of files should be stored in a different
location to the original.

15. Activity: Fill In the blank

16. Activity:
Match the
following

17. HOT

18. Plenary
List 3 Storage Devices
https://www.liveworksheets.com/do1891481pq

19. Home Work
Revise the topic

20. Car 1 Red 1.5 litersPetrol3 doors new
Car 2 Blue 1.3 litersPetrol5 doors Used
Car 3 Green 2.2 litersDiesel5 doors Used
… … … … … …
Car 20 White 1.6 litersPetrol2 doors New
field
1 2 3 4 5 6
1
2
3
4
record
FIELD + RECORD =FILE
3.2 Types of access

21. Starter
a
b
c
d
e
f
g
h
i
CD DVD or
Blu-ray
Mouse
Keyboard
Headphone
s
Scanner
USB Stick or
Memory Stick
Printer
SD Card
Sim Card

22. 3.2 Types of access
•Serial Access
•Direct Access

23. 3.2.1
Serial
access
Start at the beginning of the file and then access in
turn until the required record is found.
Primarily used on magnetic tape system
Slow form of data access

24. 3.2.1
Serial
access
When the original magnetic tape (masterfile) needs
updating, an additional tape (transaction file) is required.
The transaction file contains all the new data that the
master file needs to be updated with
New data to
be used to
update
master file
Old data
stored on
magnetic
tape
New tape
produced
from A and B
A
B

25. Serial Access

26. Where
Serial
Access is
used?

27. 3.2.2
Direct access
Used with magnetic disks, optical media
and solid state media.
Computer uses the key field to calculate
where data should be stored.
Much faster than with serial access
Used in vital data access speed such as
booking air tickets or automatic stock
control

28. Storage
Devices
and
Media

29. 3.3
secondary
storage
media
All systems of the personal computer are equipped with
some form of secondary storage.
BYTE is used to measure the size of memory or storage.
Storage size Number of bytes Number of bytes as
power of 10
1KB 1000 bytes 10
3
bytes
1MB 1 000 000 bytes 10
6
bytes
1GB 1 000 000 000 bytes10
9
bytes
1TB 1 000 000 000 000
bytes
10
12
bytes

30. 3.3 Storage
Media

31. 3.3
Storage
media
3 types of storage media:
-magnetic
-optical
-solid state

32. Magnetic Storage Media

33. Fixed
/Internal
HDD
https://youtu.be/n6uPALW
Ayxc

34. Information
HDD

35. HDD Parts

36. Uses of Fixed
HDD

37. Activity 1

38. Fixed /
internal hard
disk drives
Uses
•Store operating system, systems software and working
data/files
•Store applications software
•Used in real time systems
•Used in file servers for computer networks
Advantages Disadvantages
•Have a very fast
data transfer
rate
•Have very large
memory
capacities
•Can be easily damaged
•Have many moving
parts
•Read/write operation
can be quite noisy

44. Portable
Hard Disk
Drives
Uses Advantages Disadvantages
•Can be used as
backup systems
systems to prevent
loss of data
•Can be used to
transfer
data/files/software
between computers
•Data access time
and data transfer
rate is very fast
•They have a large
memory capacity
•They can be used as
a method of
transferring
information
between
•They can be easily
damaged if dropped
or subjected to a
strong magnetic field

45. Magnetic
tape drives
and tapes

47. Magnetic
tape drives
and tapes

51. 3.3.1
Magnetic
storage
media
Depend on the magnetic properties of certain materials
Coated on the surface of a disk or tape.
Many hard disk drive are made up of more than one disk.
These disks are called platters
Each platter is made from glass, ceramic or aluminum
coated in nickel alloy that can be magnetized.
In the case of tape, plastic that is coated in a magnetic
material is used to store the data

52. Fixed/
internal hard
disk drive
(HDD)
Store operating systems, systems software and working
data/files.
Storing applications software that needs fast retrieval and
storage of data
Used in real time systems (robots….)
Used in file servers for computer networks

53. Fixed/
internal hard
disk drive
(HDD)
advantages
They have a very fast data transfer
rate and fast access times to data
They have a very large memory
capacities

54. Fixed/
internal hard
disk drive
(HDD)
disadvantag
es
Can be easily damaged if not
correctly shut down
They have many moving parts when
compared to SSDs
Their read/write operation can be
quite noisy compared to SSDs

55. Portable
hard disk
drives
Can be used as backup systems to
prevent loss of data
Used to transfer data/files/software
between computers.

56. Portable
hard disk
drives
advantage
s
The data access time and data
transfer rate is very fast
They have large memory capacity
They can be used as a method of
transferring information between
computers.

57. Portable
hard disk
drives
disadvantag
es
They can be easily damaged if
dropped or subjected to a strong
magnetic field

58. Magneti
c tapes
In applications where batch processing is
used
Used as backup media since all data
needs to be stored
Used in long-term archiving of data;
magnetic tapes have huge data storage

59. Magnetic
tapes
advantage
s
Generally less expensive
It is a very robust technology
They have huge data storage capacity
The data transfer rate is actually fast

60. Magnetic
tapes
disadvantag
es
Very slow data access time
When updating, another tape is need to
store the final updated version
Affected by magnetic fields

61. 3.3.2 OPTICAL
STORAGE MEDIA

62. CD/DVD
disks
Laser light is used to read data and to write data on the
surface of the disk.
The data is stored in pits and bumps on the spiral track.
Can be designated as follows:
R- write once only
ROM- can only be read
RW – can be written to or read from many times

63. CD-ROM and
DVD-ROM
CD-ROM Store music files, software, computer games and
reference software
DVD-ROM have much larger storage and are used to store
films
CD-ROMs and DVD-ROM are used in applications where
there is a real need to prevent the deletion or overwriting
of important data.

64. CD-ROM and
DVD-ROM
advantages
They hold far more data than floppy disks
They are less expensive than HDD systems

65. CD-ROM and
DVD-ROM
disadvantag
es
The data transfer rate/data access time is
slower than for hard disks.

66. CD-R and
DVD-R
Home recordings of music (CD-R) and films (DVD-R)
Used to store data to be kept for later use or to be
transferred to another computer.

67. CD-R and
DVD-R
advantages
Cheaper than RW disks
Once burned they are like a ROM

68. CD-R and
DVD-R
disadvantag
es
If finalized, CD-R/DVD-R can only be recorded on once
Not all CD/DVD players can CD-R/DVD-R

69. CD-RW and
DVD-RW
Used to record television programs
Not as wasteful as R format as more files/ data can be
added to at a later stage
Used in CCTV systems

70. CD-RW and
DVD-RW
advantages
Can be written over many times
Can use different file formats each
time it is used

71. CD-RW and
DVD-RW
disadvantag
es
Can be relatively expensive
It is possible to accidentally
overwrite data

72. DVD-RAM
Used in recording devices
Used in camcorders

73. DVD-RAM
advantages
Have long life
Possible to do a rewrite operation over
100 000 times
Writing on DVD-RAMs is very reliable
Very fast access
No need to finalize
Large capacity
Offer the ability to read data the same
time as data being written

74. DVD-RAM
disadvantag
es
Not as compatible as R or RW format
Relatively expensive
Have been superseded by newer
technologies

75. BLU-RAY
DISCS
DIFFERENCE
S WITH DVDs
A blue laser, rather than red, is used to carry out read and
write operations
Using blue laser light means pits and bumps can be much
smaller
Uses a singal 1.1mm-thick polycarbonate disk
Using two sandwiched layers can cause birefringence
Blue-ray discs automatically come with a secure
encryption system

76. BLU-RAY
DISCS
Used in home video consoles
Storing and playing back movies
PCs can use this tech for data storage or backing up hard
drives
Camcorders can use this media to store movie footage

77. BLU-RAY
DISCS
advantages
Very large storage capacity, therefore ideal for storing
high-def movies
Very fast data transfer
Data access speed is l=also greater than with other optical
media
Blu-ray discs automatically come with a secure encryption
system

78. BLU-RAY
DISCS
disadvantag
es
Relatively expensive
Encryption problems
Fewer movie titles on Blu-ray format, which is reducing its
impact on the home movie market

79. SSD
Taking over HDDs
Include: memory sticks/pen drives, flash memory cards