Secondary storage devices hold information regardless of whether the computer has power. Examples include hard disk drives and floppy disks. While primary storage is faster, secondary storage is needed for today's computers to store programs and personal data due to limitations on primary storage sizes and prices. Common secondary storage devices discussed include hard disks, CD-ROMs, CD-Rs, USB flash drives, and memory cards.

1. Presented by: Charmaine Eclavia

2. Secondary storage
-is a storage medium that holds
information until it is deleted or
overwritten regardless if the computer
has power. For example, a floppy disk
drive and hard drive are both good
examples of secondary storage devices.

3. As can be seen by the below
picture there are three different
storage on a computer, although
primary storage is accessed
much faster than secondary
storage because of the price and
size limitations secondary
storage is used with today's
computers to store all your
programs and your personal
data.

5. Hardware Devices: Secondary
storage devices
Hard Disk

6. Hard disks are usually found inside
computers to store programs and
data. They are increasingly cheap
and more and more companies are
using them to back things up. Hard
disks can vary in physical size with
some disks getting as small as your
thumb. The capacity of a commercial
disk is currently up to about 4
terabytes allowing users to read and
write to them. They are constructed
from several key components

7. Platter - Metallic disks where One or
both sides of the platter are
magnetized, allowing data to be
stored. The platter spins thousands of
times a second around the spindle.
There may be several platters, with
data stored across them
Head - The head reads magnetic data
from the platter. For a drive with
several platters there may two heads
per platter allowing data to be read
from top and bottom of each

8. Actuator Arm - used to move the read
heads in and out of the disk, so that
data can be read and written to
particular locations and you can
access data in a Random fashion,
you don't need to read your way
through the entire disk to fetch a
particular bit of information, you can
jump right there. Seek time is very
low.
Power connector - provides electricity
to spin the platters, move the read
head and run the electronics

9. IDE connector - allows for data
transfer from and to the
platters
Jumper block - used to get the
disk working in specific ways
such as RAID

11. CD-ROM

12. A CD-ROM is a metal disc embedded
into a plastic protective housing. Each
disc has to be 'mastered'; this is the
process of creating the CD and
placing the data on it. CDs are
WORM (Write Once, Read Many)
media; this refers to the fact that once
they have been mastered, there is no
way to change the data on them.

13. Writing to a CD-ROM
A single track runs in a spiral pattern
from the centre of the disc to the
outside, this track is made of pits and
lands to represent the ones and
zeroes of binary data
A high-powered laser is shone onto the
CD-ROM, burning pits into the metal
The disc spins and the laser follows the
track, putting the binary data onto the
CD in a spiral track
The data has been written

14. Reading from a CD-ROM
A single track runs in a spiral pattern
from the centre of the disc to the
outside, this track is made of pits and
lands to represent the ones and
zeroes of binary data
A low-powered laser is shone on the
metallic surface and the reflection is
captured in a photodiode sensor, the
lands reflect differently to the pits,
meaning it can tell the difference
between a 1 and a 0

15. The disc spins and the laser follows the
track
The binary data (the 1s and 0s) are put
together and the CD-ROM has been
read

16. CD-R
The CD-R is made of a
reflective metal disk with a
layer of (usually green,
opaque) dye on top.

17. Writing to a CD-R
A single track runs in a spiral pattern
from the centre of the disc to the
outside.
A high-powered laser is shone onto the
CD-R, changing the transparency
(permanently) of the dye above. The
transparent and opaque parts
represent binary 1s and 0s
The disc spins and the laser follows the
track, putting the binary data onto the
CD-R in a spiral track
The data has been written

18. Reading from a CD-R
A single track runs in a spiral pattern
from the centre of the disc to the
outside, this track is made of pits and
lands to represent the ones and
zeroes of binary data
The binary data (the 1s and 0s) are put
together and the CD-R has been read

19. A low-powered laser is shone on the
surface and the reflection is captured
in a photodiode sensor. The opaque
dye will reflect differently to the
transparent dye (which would just
reflect the metal underneath it),
meaning it can tell the difference
between a 1 and 0
The disc spins and the laser follows the
track

20. USB(Memory Stick)Flash Drive

21. USB Flash drives are solid state, that
means that there are no moving parts.
This is very useful for seek times as
we don't have to wait for mechanical
movement, meaning seek time is very
low and it allows for fast Random
Access Memory. Flash drives can be
set to read only mode, but they will
always allow for reading and writing.
The size of flash drives is not as great
as a Hard Disk and they are generally
much more expensive per megabyte

22. Memory cards
Work in much the same way as a Flash
drive and can often be converted into
Flash Drives. They have different
connectors and are generally smaller
than USB Flash drives allowing for
them to be used in cameras, mobile
phones and game consoles.

24. EVALUATIO
N

25. Question
This is a storage medium that holds
information until it is deleted or
overwritten
A. External Memory B. Auxilary storage
C. Primary Storge
D. Secondary Storage

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Question

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28. It is usually found inside computers to
store programs and data.
A. Hard Disk
B. USB
C. CD-ROM D. CD-R

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Question

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31. Work in much the same way as
a Flash drive and can often be
converted into Flash Drives.
A. Memory Card
B. Flash Drive
C. CD-ROM D. CD-R

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Question

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34. Metallic disks where One or
both sides of the platter are
magnetized, allowing data to
be stored.
A. Actuator Arm
D. Head
C. Arm
B. Platter

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Question

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37. Provides electricity to spin the platters,
move the read head and run the
electronics
A. Platter
C. Power Connector
B. Head
D. CPU

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40. CONGRATULATION
S