Robert Crawford, MBA
West Middle School
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Summarize how a CPU and RAM work
together
Contrast primary and secondary storage
Compare the features of four secondary
storage devices
Identify three types of peripherals and the
types of connectors that use each
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Central Processing Unit (CPU)
Cloud Storage
Hardware
Random Access Memory (RAM)
Universal Serial Bus (USB)
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Well, what is hardware?
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The computers physical parts are its
hardware.
e.g.
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Keyboard
Mouse
Processor
Power supply
Monitor
...
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Much of the computers hardware is found
inside of the case, hidden from view.
This includes:
◦ Processing devices
◦ Primary storage
◦ . . . Some secondary storage (but this is changing
rapidly)
 (Cloud computing, wake from LAN)
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Processing Devices
◦ A central processing unit (CPU) (formerly also
referred to as a central processor unit) is the
hardware within a computer that carries out the
instructions of a computer program by performing
the basic arithmetical, logical, and input/output
operations of the system.
◦ It is a very small circuit board covered with tiny
electronic devices.
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Primary Storage
◦ Random Access Memory (RAM) is a form of primary
memory
 RAM access memory is compared to sequential access
memory (seldom used) and ROM (read only memory).
 We will talk about ROM in a future unit.
 A random-access memory device allows data items to
be read and written in roughly the same amount of
time regardless of the order in which data items are
accessed.
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Secondary Storage devices
◦ The primary feature of secondary storage devices is
that they allow you to store your data permanently;
even after the power is turned off.
◦ Examples of secondary storage devices include:
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Hard Drives
USB Drives (flash, jump, or pen drives)
Compact Discs
Cloud Storage
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Secondary Storage devices
◦ Examples of secondary storage devices include:
 Hard Drives
 A hard disk drive (HDD) is a data storage device used
for storing and retrieving digital information using
rapidly rotating disks (platters) coated with magnetic
material.
 Data is read in a random-access manner, meaning
individual blocks of data can be stored or retrieved in
any order rather than sequentially. An HDD consists of
one or more rigid ("hard") rapidly rotating disks
(platters) with magnetic heads arranged on a moving
actuator arm to read and write data to the surfaces
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USB – Universal Serial Bus
A USB flash drive is a data storage device that
includes flash memory with an integrated
Universal Serial Bus (USB) interface. USB flash
drives are typically removable and rewritable,
and physically much smaller than an optical
disc.
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Compact Discs
◦ Compact disc (CD) is a digital optical disc data
storage format. The format was originally
developed to store and play sound recordings only
(CD-DA), but was later adapted for storage of data
(CD-ROM).
◦ At the time of the technology's introduction, it had
much greater capacity than computer hard drives
common at the time.
 The reverse is now true, with hard drives far exceeding
the capacity of CDs.
 Compact Discs
Diagram of CD layers.
A. A polycarbonate disc layer
has the data encoded by
using bumps.
B. A shiny layer reflects the
laser.
C. A layer of lacquer protects
the shiny layer.
D. Artwork is screen printed
on the top of the disc.
E. A laser beam reads the CD
and is reflected back to a
sensor, which converts it into
electronic data
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Cloud Storage
◦ Cloud storage is simply a term used to describe the
various web sites that provide on-line storage.
 Some are free (up to some limit) and some are not.
Advantages
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Companies need only pay for
the storage they actually use
Organizations can choose
between off-premises and onpremises cloud storage options,
or a mixture of the two options.
Storage maintenance tasks,
such as purchasing additional
storage capacity, are offloaded
to the responsibility of a service
provider.
Cloud storage can be used as
natural disaster proof backup.
As normally there will 2 to 3 of
different backup servers located
in different places around the
globe.
Disadvantages
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When data is distributed it is stored at
more locations increasing the risk of
unauthorised physical access to the
data.
◦ The number of people with access to
the data who could be compromised
(i.e. bribed, or coerced) increases
dramatically.
It increases the number of networks
over which the data travels. Instead of
just a local area network (LAN) or
storage area network (SAN), data stored
on a cloud requires a WAN (wide area
network) to connect them both.
By sharing storage and networks with
many other users/customers it is
possible for other customers to access
your data.
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Processing devices
Primary Storage
◦ RAM
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Secondary Storage Devices
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Hard Drives
USB Drives
Compact Disks
Cloud Storage
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Processing devices
Primary Storage
◦ RAM
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Secondary Storage Devices
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Hard Drives
USB Drives
Compact Disks
Cloud Storage
 Which of these secondary storage devices is best?
 Here is a hint, the right answer is “it depends.”
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Hardware that is separate from, but can be
connected to, the computer case is called a
peripheral.
◦ This can include:
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Keyboards
Mice
Printers
Monitors
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Cables
◦ Peripherals are typically connected to the computer
by some type of a cable and plug.
◦ The plug joins to the connector in the computer
case.
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Connectors
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What is RAM?
How do primary and secondary storage differ
Name four secondary storage devices and
identify something at each is best at (name
an advantage of each)
Identify three types of peripherals and the
types of connectors that use each.
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Key terms
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Central Processing Unit (CPU)
Cloud Storage
Hardware
Random Access Memory (RAM)
Universal Serial Bus (USB)