1. Storage
Unit 1 – Understanding Computer Systems
JMW 2012

2. Get your brains logged on!
Put these terms in order (smallest to largest):
A. Terabyte
B. Megabyte
C. Bit
D. Gigabyte
E. Byte
F. Kilobyte

3. Get your brains logged on!
Put these terms in order (smallest to largest):
C. Bit 1 bit
E. Byte 8 bits
F. Kilobyte 1000 bytes
B. Megabyte 1000 kilobytes
E. Gigabyte 1000 megabytes
A. Terabyte 1000 gigabytes

4. By the end of this lesson:
• All of you would be aware of the units used to
measure storage on a computer.
• Most of you should be able to explain the
advantages and disadvantages of the main
storage technologies.
• A few of you could consider the impact of
cloud storage on the way people store data.

5. Different storage technologies
Optical Magnetic Flash (Solid State)
YOUR TASK: Find out the following for
each of the above storage technologies :
a) How is data stored?
b) Provide some examples of storage devices that use that
technology, e.g. CD for Optical.
c) What are the advantages of that storage technology?
d) What are the disadvantages of that storage technology?

6. Optical
How does it work? Examples of optical devices:
Advantages: Disadvantages:

7. Optical
Source: http://static.howstuffworks.com
CDs, DVDs and Blu-ray discs (all optical media) contain small “bumps” that you
can’t feel with your finger but can be picked up by the laser.
When the laser hits a bump it bounces into the optical pickup and this is
converted into a digital signal – like the turning the light on and off.
Optical discs are very cheap and quick to produce but can be easily
damaged/scratched.

8. Magnetic
How does it work? Examples of magnetic devices:
Advantages: Disadvantages:

9. Magnetic
Drive read/write Other examples of magnetic
head media are:
Source: http://www.ramdisc.com/
Floppy Disk
Digital Tape
(very cheap
and large
capacity)
Similar to an optical drive, the drive head moves across the spinning magnetic
disk, but instead of bumps it picks up small changes in polarity.
Hard drives can contains lots of data (large capacity) and quite cheap to buy.
However, when the a hard drive crashes that means the head has literally
crashed into the spinning disk – easy to damage, especially when you drop in!

10. Flash (Solid State)
How does it work? Examples of solid state devices:
Advantages: Disadvantages:

11. Flash (Solid State)
• Unlike optical or magnetic – there are no
moving parts… more reliable.
• Can be smaller, faster, more portable and use
less energy… but can also be more expensive!
The iPhone
uses flash
memory
instead of a
magnetic
hard drive.

12. Cloud Storage
• Cloud storage is when you store data online
on a remote computer and access it via the
Internet.
• Web-based mail is a form of Cloud storage as
your emails are stored on the mail provider’s
website.
• Facebook or Flickr are forms of Cloud storage
as they store images that you have uploaded.

13. Your Task: Which technology?
• Go to Studentshare > Subjects > ICT > Y9 >
Unit 1 > Which Storage Exercise.
• Use the information from your research and
the information your teacher has provided to
answer the questions.
• This powerpoint is available in the same folder
if you need to refer back to it.

14. Cloud Storage
• Can you think of the advantages of using cloud
storage?
– Why do people use it?
– What are the benefits of storing data online?
• Can you think of any disadvantages of using
cloud storage?
– What are the risks?
– What do we need to be careful of?

15. Cloud Storage
• Accessible on any computer with Internet access (anywhere in
the world!)
• Cloud provider will take care of backing up your files for you.
• Easier and quicker to share files with other people.
• Easier to sync with other devices you may own, e.g. iCloud
makes it easier for your iPad, iPhone and mac to share files.
• Security - anyone could access your data if they hacked your
password or the system.
• Could lose files if cloud provider’s computers failed and
backups didn’t work – unlikely as if this ever did happen the
company would never be trusted again and would go bust!
• Need good Internet connection to download/upload files,
especially photos, videos and music.
• Cost – is it free or it there a monthly charge for storage?

16. Knowledge Check
1) What type of storage technology does a blu-
ray disc use?
A) Optical
B) Magnetic
C) Solid-state (Flash)

17. Knowledge Check
3) Which storage technology would you
recommend for a smartphone?
A) Optical
B) Solid-state (Flash)
C) Magnetic

18. Knowledge Check
3) Which one of these advantages of magnetic
storage technology is the ODD ONE OUT?
A) Large capacity
B) No moving parts
C) Cheap