Unit 4 Hardware and Networks

Unit 4 Hardware and Networks
Information System Design &
Development
National 5
Hardware and Networks
Hardware
An essential part of designing an information
system is the selection of suitable hardware.
Memory: RAM & ROM
The main memory of a computer comprises RAM
and ROM. Random access memory (RAM) is the
largest part of the main memory, storing the operating system, programs and
data while the computer is switched on.
The main differences between RAM and ROM are that ROM is small
permanent memory that does not get written to by the user during normal
operations whereas RAM is larger, temporary storage which loses its contents
when the computer is switched off.
People often get confused between main memory and backing storage, they
are not the same.
Main memory is located inside the computer system. It can either
be RAM or ROM.
Backing storage is outside the main processor, e.g. Hard Drives,
CD/DVD drives, USB Flash Memory (Pen Drives).
Main memory in today’s computers is on average around 4-6 Gb of RAM.
Backing Storage is much bigger with average computers having around 1 Tb
or more.
ROM (Read Only Memory)
ROM is used to store a small part of the operating system called the bootstrap
loader.
• Data is stored permanently in ROM, it is not lost when the power
goes off
• Data in ROM cannot be changed
• ROM holds vital systems data programs.
2
RAM (Random Access Memory)
•
•
•
•
The processor can write to and read from RAM at high
speed
Data held in RAM can be changed
All data in RAM is lost when the power is switched
off
RAM is the working space of the computer. It holds all of
the programs and data files currently in use.
Measuring the size of memory
We use these terms when measuring computer memory.
Bit
Byte
Kilobyte
Megabyte
Gigabyte
Terabyte
Binary digit : a single 1 or 0
8 Bits, for example 11001110
1024 bytes
1024 Kilobytes
1024 Megabytes
1024 Gigabytes
Watch the video – “RAM and ROM”
The Central Processing Unit - CPU
The CPU or processor is the brain of the computer, controlling
everything that takes place on the computer, e.g. movement of
data and any calculations to be carried out.
Most computers today have more than one processor working
together to improve system performance. The processors on mobile phones
and tablets will be different to the ones on a normal desktop. These mobile
processors might not be as powerful as the desktop equivalent but will be
designed to use less power so that the battery on the phone or tablet lasts
longer. In addition to this, different companies compete with one another in
the processor market and different computer manufacturers can use differing
processor types, which can make comparing computers difficult.
A processor is made of silicon crystal wavers, which hold millions of tiny
electronic components.
3
Processor Types
Multiple core processors
These have two or more processors working together to make the system
work better. For example there are duo-processors, with two or more
processors working together, quad processors, with four processors working
together and even hex-core processors with six processors.
Low Power Processors
These have lower clock speeds and use less electricity. They are used in
laptops, net books, mobile phones, MP£ players, tablet computers and games
consoles.
Watch the video – “Computer Hardware _What is a
Processor”
Clock Speed
Clock speeds are a measure of how powerful a processor is, for example
3GHz. Clock speeds are measure in Megahertz (MHz) or Gigahertz (GHz). 1
MHZ = 1 million pulses per second; 1GHz = 1000 million pulses her second.
The clock pulses measured in GHz, regulate and coordinate the activities in
the processor.
1000 million pulses per second - this measures how many times per second
the system clock pulses. If the computer carries out an instruction or
calculation with every pulse of the system clock then the faster the system
clock ticks or pulses, the more operations will be carried out per second.
Unfortunately it isn’t as simple as just comparing clock speeds of computers
because as there are a wide number of processor types and manufacturers
on the marketplace and they perform differently so other measures need to be
taken into account as well, such as the amount of memory a computer has
installed.
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Below is an example of a typical processor type and speed.
Apple iMac
Processor
2.9GHz quad-core Intel Core i5 processor
(Turbo Boost up to 3.6GHz) with 6MB L3
cache
Watch the video – “Clockspeed”
Exercise
1.
Which part of the computer controls everything that happens within it?
2.
What is the name of the basic measure of a computer processor’s
performance?
3.
What is the unit of measurement for the measure mentioned in question
2?
4.
Research and list three different companies that manufacture computer
processors.
5.
Which one of these statements about RAM and ROM is true?
A
B
C
D
Neither ROM nor RAM holds data when the power is switched off.
RAM holds data when the power is switched off and ROM doesn't.
The user can write data to RAM but not to ROM.
The user can write data to ROM but not to RAM.
6.
Which generally holds more data, RAM or ROM?
7.
When a computer is first switched on, which type of memory is read from
first and why?
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Backing Storage
When we talk about ‘storing’ data, we mean putting the data in a known place.
We can later come back to that place and get our data back again.
‘Writing’ data or ‘saving’ data are other ways of saying ‘storing’ data.
‘Reading’ data, ‘retrieving’ data or ‘opening’ a file are ways of saying that
we are getting our data back from its storage location.
Backing storage devices are used to store the programs and data that the
computer can access. The contents of backing storage are not lost when the
power to the computer system is turned off.
There are two ways to access data on a backing storage device: randomly or
sequentially. Random access means that particular files can be jumped to
without having to read through all of the data, in the same way a user might
select a track from a CD or a scene from a DVD. With sequential access, the
user has to run through all of the data to find a file (similar to fast forwarding
on an old video tape).
Type of access
Backing storage device
Random/direct
Hard disk drive, memory cards, flash drive, CD,
DVD and blu-ray drives
Sequential/serial
Magnetic tape drive
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Magnetic
Magnetic
Capacity
Hard Drives
Magnetic Tapes
Floppy Disk
Zip Drive
500Gb – 1Tb
1.44Mb
750Mb
Hard Disk
The hard drive is the main storage device for programs and files on personal
computers. They have a very large storage space, usually measured in
gigabytes (but some are now into terabytes).
This is a metal disk with magnetised surfaces on which data is stored as
patterns of magnetic spots. The disks are in sealed units to stop dust and dirt
corrupting data. They are usually fixed in the computer but you can get
portable external drives.
Advantages
Fast access times, direct access
Fast data transfer rates
Cheap per megabyte.
Watch the video – “Hard Drives”
Magnetic Tape
These small cassettes (similar to old 8mm video camera or audio cassettes)
are mainly used as backup systems for large networks. The tapes can store a
lot of data but retrieving data can be slow as the user has to fast forward and
rewind through the tapes to get to the data.
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Optical Storage
Optical
Capacity
CD-ROM
CD-R
CD-RW
DVD-ROM
DVD-R
DVD-RW
Blu-Ray
700Mb
700Mb
700Mb
4.7 - 17Gb
4.7 - 17Gb
4.7 - 17Gb
25Gb
These disks use lasers to read data ‘burnt’ onto the disk surface.
Read-Only storage devices such as CD-ROM, DVD-ROM and Blu-Ray have
data written onto them when they are manufactured. This data cannot be
changed.
CD-ROM
CD-ROM stands for Compact Disk – Read Only
memory. It is fast and can store up to 700 Mb of data.
It cannot be written to – the data is fixed at the time of
manufacture. The data is read by a sensor that detects
laser light reflected from the surface of the disk. The
speed of a CD drive is given as a number, for example
52X (52 X 150 Kilobits per second).
Used to distribute all sorts of data: software (e.g. office applications or
games), music, electronic books, (e.g. an encyclopaedia with sound and
video.)
CD-R
This is CD-recordable – it allows you to record data once. One data is
recorded on it, it works just like a CD-ROM. It is read only. It can hold 700
Mb of data. The speed of a CD-R drive is given as two numbers, the read
speed and the write speed.
CD-RW
This is rewriteable so you can record data over and over again, just like hard
disks. You can use them to make backups of large files, for example groups
of photos, and you can change the data stored on the disk as often as you
want.
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DVD-ROM
A DVD-ROM uses optical technology to read data. Like a
CD-ROM it is read only.
A DVD-ROM has much larger data capacity than a CDROM. Single-sided single layered DVDs have a capacity of 4.7 GB. Doublesided, multi-layered DVDs have a capacity of 17 GB.
The speed of a DVD-ROM drive is given as a number, for example 16X. This
is different from a CD, as each 1X is 1250 Kilobits per second.
DVDs are used in the same way as CD-ROMs but, since they can hold more
data, they can also be used to store high-quality video.
DVD-R
DVD-recordable allows you to record data once. After recording the data
cannot be changed. They have the same capacity as DVDs but a DVD-R
drive has two speeds, one for writing and one for reading data, for example,
Write 6X, Read 12X.
DVD-RW
This is a DVD that allows you to record data over and over again. Like hard
disks, you can use them to make backups of very large files, such as home
movies from your digital video camera and you can change the data stored on
the disk as often as you want.
A DVD-RW drive has three speeds; one for writing data, one for rewriting and
one for reading, for example. Write 6X, Rewrite 2.4X and Read 12X.
Blue-Ray Discs
Blu-Ray discs are used in the same way as DVD-ROMs but,
since they can hold more data, they are also used to store very
high-quality, high-definition (HD) video.
Watch the video – “How do CD’s work”
“How (CD) Compact Discs Work”
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Solid State
Solid State
Capacity
USB Flash Drive
SSD Drive
SD Card
1Gb-512Gb
256Gb
1Gb-16Gb
The term ‘solid-state’ essentially means ‘no moving parts’.
The most common form of portable backing storage is the
USB flash drive. Also called pen drive or memory stick the
flash drive shown in the photograph on the right is a small
portable backing storage device with no moving parts.
This type of backing storage plugs into the USB port of a
computer, making them a convenient way of keeping a backup copy of files
and of transferring files from one computer to another.
Flash drives can store large amounts of data up to 512Gb.
Memory Cards
Mainly used in small electronic devices such as digital cameras, MP3 players
and mobile phones, memory cards are usually read by connecting the device
containing the card to the computer or by using a USB card reader. Memory
cards are small, light and again have no moving parts. Despite the small
physical size some types of memory card can hold many gigabytes worth of
data.
In summary solid state storage devices are
• Re-writable
• Ultra-Portable (fits in your pocket)
• Good capacity size for transferring files such as large documents or
photos.
Watch the video – “Explaining SD Cards”
“Explaining Solid State Drives”
“USB - Universal Serial Bus”
“Explaining USB 3.0”
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Portable Hard Drive
A portable hard-drive is one that is placed into a small case
along with some electronics that allow the hard-drive to be
accessed using a USB or similar connection.
Portable hard-drives allow very large amounts of data to be
transported from computer to computer.
Exercise
1.
Which of these is a backing storage device?
A
C
Scanner
Printer
B
D
Flash drive
Speakers
2.
What type of access is used by a magnetic tape drive?
3.
Use the internet to research the current cost and capacity of the backing
storage media mentioned on the previous page. Put your findings into a
table, sort the table from lowest value storage to highest value storage,
print this list out and save your table.
4.
Using the table created in question 3, perform another sort but this time
for capacity in descending order from highest capacity to lowest
capacity.
5.
What is meant by the term ‘solid state’?
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Input Devices
An input device is a piece of hardware that lets you put information onto or
into a computer to be processed.
Digital Camera
This is a camera for taking digital pictures. The quality is
measured in megapixels; the number of millions of detectors
in the grid that detects the picture. A reasonably good one will
be 16 megapixels and will cost less than £80. Advantages: they can hold lots
of images without film, you can delete the pictures you don’t want, you can
also transfer them to a computer and print them out easily.
Digital images can be taken of an event such as a birthday party and then be
transferred to a computer, edited and shared online with others.
Microphone
Allows sound to be input to the computer. Microphones are
used to take a sound and convert it into an electrical signal for
the computer.
Recording narration for a video.
Used in conjunction with voice recognition software to give commands to the
computer or to take the spoken word and convert to text on screen.
Joystick or Joypad
Joysticks or joypads are used mainly in games to give the
user control over the game objects like a car, a plane or a human character.
Controlling a game using a joystick or joypad is much easier than using the
keyboard and mouse.
Playing computer games
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Webcam
Webcams are digital cameras that are used to take photographs. The
photographs are then transferred to a web page and then sent across the
Internet.
Used to view traffic flowing along motorways and to advertise tourist
attractions and business sites.
Touchpad
A small, flat pad which senses your finger movements and
uses this to control the cursor on the screen and select icons
and menus. More convenient for use with a laptop where it
is difficult to use a mouse.
Similar to a mouse it can be used to select items from a menu or highlight
objects on screen to be edited.
Scanner
Used to input images to a system. A light beam passes over
the page or photo and a sensor detects the light being
reflected, i.e. the light bits. This information is changed into
binary values for light and dark and saved to a file.
Digitising a traditional photo on photo paper so that it can be edited and
shared with others, for example on a website.
Mouse
A pointing device used to interact with graphical user
interfaces on screen. The hand-sized case has at least one
button on top and (usually a laser fitted underneath.
Sensors detect the movement of the mouse relative to the surface
underneath,. The mouse is used to control the cursor on the screen and to
manipulate icons and menus.
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Keyboard
A normal keyboard has keys for the letters of the
alphabet, keys to produce the digits from 0 to 9, keys
to produce all punctuation marks and special
command and function keys.
Typing an essay up in a word processor.
Typing in numbers/data for a sales spreadsheet.
Typing in a web address (URL) for a website.
Graphics Tablet
A graphics tablet is a flat pad with electronic sensors
below the surface. These detect the movements of a
pointing device (stylus) and move the cursor on the
screen accordingly. What is drawn or written on the pad
will appear on the screen.
This system has the advantage of being very sensitive and accurate and is
used in engineering and design systems.
Output Devices
An output device enables a computer to communicate with the outside world.
Brief descriptions of some common out devices are given below.
LCD Screens
LCD screens use transistors and a thin film of liquid crystals
to control the light passing through the screen. They are
found on palmtops and laptops, smartphones and tablets
because they are light, compact, need little power and can
be run on batteries. One problem is that some LCD screens
are not very bright and can cause eye strain if they are used
for too long.
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TFT Screens
TFT is a type of LCD screen that uses lots of
transistors to produce a high quality display. A TFT
screen can display animations and threedimensional graphics much more clearly than
ordinary LCD screens. The disadvantage is that
they can be a lot more expensive than ordinary LCD
screens.
On desktop computers TFT screens are used
because they take up less space on a desk than CRT, (cathode ray tube),
monitors and less awkward to move around.
Inkjet Printer
Uses ink cartridges and sprays fine jets of ink onto the paper
to form letters. Inkjet printers can produce high-quality
printouts and are cheaper to purchase than laser printers.
However running costs can be high as the toner is expensive,
(and dries out if you don’t use it often). They are also a lot
slower than laser printers.
Home use, to print off short letters or colour photos.
Laser Printer
A laser printer works by using a laser beam to put the image of
a page onto a photosensitive drum. The toner or ink then sticks
to the charge drum. This is then transferred to paper and fused
by heat to make it stick. They are very fast and produce very
high quality output. However, they can be more expensive to buy than an
inkjet.
Business use to print out long documents or multiple copies of reports quickly.
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How to Compare Printers
You compare printers using the following criteria:
Speed
This is measured in pages per minute (ppm), for example 8
ppm.
Resolution
The higher the resolution, the more dots per inch, (dpi), the
better the quality of the printout. Printouts for a printer
capable of 900 dpi will be poorer in quality than those from a
1200 dpi printer.
Cost
Capital cost: the initial cost of buying the printer. Running
costs: the cost of toner or ink, (and paper).
Speakers
These are used for outputting sound; how loud the speakers are
is generally measured in watts.
To provide sound for a multimedia presentation.
To allow the user to hear the dialogue in a DVD being played on the
computer.
Graphics Card
These cards have on-board memory that is dedicated to
handling graphics. This relieves the main CPU, allowing it to
concentrate on other tasks. The graphics card takes digital
information about the graphics stored in the RAM then sends it
out to control the colours and refresh the image on the screen.
Allows a user to play high-quality, first-person, shooter games.
Allows a user to edit and produce high-definition video.
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Sound Card
Similar to a graphics card, sound cards have on-board memory
that is dedicated to handling sound, relieving the main CPU and
allowing it to concentrate on other tasks. The sound card takes
digital information about the sound stored in the
Allows a user to enjoy high-quality, immersive surround sound, whilst playing
first-person shooter games.
Allows a user to edit and produce high-quality audio.
Exercise
1.
What does the L in LCD stand for?
A
B
C
D
2.
What is the smallest measure of storage size?
A
B
C
D
3.
Kilobyte
Megabyte
Byte
Bit
Which of these is an input device?
A
B
C
D
4.
Lighter
Links
Liquid
Laser
Speakers
Monitor
Digital camera
Printer
Which of these is an output device?
A
B
C
D
Scanner
Mouse
Keyboard
Monitor
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Types of Computer
You need to know about the following devices:
• Supercomputer
• Desktop
• Laptop
• Tablet
• Smartphone
• Embedded
• Server
Mainframes and Supercomputers
These computers are very large physically,
generally positioned in specially designed
rooms with air conditioning, uninterruptable
power supplies and enhanced physical and
electronic security.
Mainframes are used for large organisations
like banks to perform a high volume of
important tasks simultaneously, whereas
supercomputers are generally used by
scientists to crunch massive amounts of data to perform a specific complex
calculation, e.g. scientific research, medical research, forecasting the weather
and modelling climate change. Both types of computer process data
extremely fast and have massive amounts of memory, multiple powerful
processors that allow a large numbers of users to access the system at once.
Desktop
These computers are not portable and are
powered by mains electricity rather than by
battery. A desktop will have a monitor, fullsized keyboard, mouse and optical DVD or
blu-ray drive.
Laptop
A laptop:
• Is small enough to use on your lap
comfortably
• Is useful for working away from the home
or office
• Is light, weighing less than 4kg and can
be carried easily
• Is powered by batteries, (or by mains
adapter)
• Has an LCD or TFT screen
• Has standard keyboard and a touchpad as well as a range of disk
drives.
Tablet
A tablet is a mobile computer with:
• a flat touch screen usually between 7 and
10 inches in size
• a screen resolution commonly around 1200
x 800
• a processor with a speed around 1.5 GHz
• memory capacity between 16 and 64 Gb
• a battery with a life of around 10 hours
before recharging
• an Internet connection
Smartphone
A smartphone:
• Is a mobile phone with a memory to hold an
address book and ring tones; and the ability
to send, receive and store text messages
• Is a multimedia device that can handle text,
graphics, audio and video
• Has a browser to access web pages and
send email
• Has a digital camera to capture images and
send them through the phone network and the Internet
• Can play MP3 files and games
• Can connect with laptops and desktops.
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What is an Interface?
The interface is the combination of hardware and software needed to enable
the processor in a computer to communicate with the external devices. You
need an interface to connect your computer to external devices like a printer
or an external hard drive or USB flash drive.
When looking at an interface it is important to consider the speed of data
transfer, or how quickly data is sent to and from the device. The slower the
interface speed the longer a user has to wait to copy or save files.
What does an Interface do?
An interface will do jobs like:
• change electrical voltages
• deal with control signals
• change analogue data to digital form
• store incoming data so that the processor can get on with other tasks.
Interface Type
Transfer Rate
USB 2.0
480 Megabits per second
FireWire 800
up to 800 Megabits per second
Express Card
up to 2.5 Gigabits per second
USB 3.0
up to 5 Gigabits per second
SATA
up to 6 Gigabits per second
Thunderbolt
up to 10 Gigabits per second
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Exercise
1.
Which type of computer controls and distributes resources on a
network?
A
B
C
D
A server
A tablet
A palmtop
A bottletop
2.
What type of computer might be used for a large and complex scientific
project?
3.
Put the following devices in order of physical size with the smallest first:
laptop, desktop, smartphone, tablet.
Activity: Device Investigation
Research each of the following:
• Desktop PC
• Laptop
• Tablet
• Games Console
• Smartphone
• Mainframe
Types of Computer System Research
Processor
Cost (£)
(GHz)
RAM (Gb) Storage (Gb)
Name
Apple iPad 3
Tablet
£479.99
Dell Studio Laptop £399.44
1
2.4
1
4
32
500
Present your findings in a spreadsheet as shown above.
When you have got the information for each of the devices create a graph
with the information for each piece of info (1 graph for cost, 1 for processor
etc.).
Do you see any trends?
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Operating System
Some people would say that the operating system is the most
essential software on a computer system. The operating system
is the first program to load up when a computer is powered up
and contains a program or set of programs that control how the
computer functions. Without an operating system installed the computer is just
an expensive lump of metal and plastic.
Watch the video – “Computer Basics - The Operating
System”
Functions of an Operating System
The operating system carries out important functions on the
computer. They:
•
•
•
•
•
Manage the use of both the internal memory and backing store
Manage the files and keep track of where they are stored in the system
Provide the user with an interface usually a graphics-based interface,
increasingly with a touch screen and even voice input
Run other software
Control the use of devices such as printers.
Exercise
1.
Research and list as many operating systems as you can.
2.
Swap your list from question 1 with another pupil, tick the ones you had
on their list and add any others they didn’t have. Make a note of any
names you didn’t have on your list and make sure to add them to yours.
3.
What must be taken into account when designing an operating system
for smartphones and tablets?
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Networking
Stand Alone or Networked
Most computer systems today are connected to a network most of the time or
at least some times.
If a computer is not connected to a network it is called a stand alone
computer. Even though it is not connected to a network it will certainly have
the capability to do so.
Scale of a Network
Networks can be categorised into two main types based on their scale or size.
There are Local Area Networks and Wide Area Networks.
Local Area Network (LAN)
A group of linked computers in close
proximity to each other, such as in an
office building, a school or at home.
LANs are useful for sharing resources
such as files, printers or other
applications.
The computers can be linked using
copper cables or by a wireless
connection.
Watch the video – “What is a LAN (Local Area Network)”
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Wide Area Network (WAN)
A WAN covers a large
geographical area, such as a
city, county or country.
Most WANs are made from
several LANs connected
together.
The internet is a global network of
networks where many LANs and
WANs are interconnected.
Watch the video – “What is a LAN and WAN”
Internet
The internet is a global system of interconnected computer networks.
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•
•
•
•
It has a number of different elements:
The World Wide Web which is made up of multimedia web pages that
are stored on computers across the world. Web pages hold text,
sounds, graphics, animations and videos. These are linked by
hyperlinks.
Search engines to help users find their way around the Internet.
Forums and chatrooms where you can meet people and discuss all
sorts of topics.
The Internet has many uses, for example sending email, social networking,
(Facebook), Twitter), online shopping and banking.
Wireless
Wireless networking involves computers and devices
communicating with one another without any cabling.
Wireless networks use radio waves, microwaves or
infrared light to transmit data. All you need is a
transmitter/receiver in every machine and a central device,
such as a wireless router, to pass the data around the
network.
Any modern computer can be fitted with a wireless network card, sometimes
by just plugging it into the USB.
Advantages
Wireless networks are easy to install, as there is no need for cables. Also you
can move around when you work without trailing wires. They have
reasonably fast transmission speeds, although they can be slower than
physical cables.
The main problem is that they are very vulnerable to hackers, who can just
‘tap in’ to your signal. You need to take care when setting up network security
if you don’t want other to access your files or use you internet connection.
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The downside to wireless networking is that the bandwidth or speed of
transmission is generally slower than a wired connection.
Bluetooth is a wireless network technology that allows devices like mobile
phones, printers, headsets and laptop computers to form mini-networks when
they are in close proximity to each other.
Some businesses will use wireless as it saves money not having to lay down
all the cable.
Wired Networks
Here are some types of wiring used on LANs
Twisted Pair
The most common type of networking cable is twisted
pair or ethernet cabling. This cable consists of two
copper wires twisted around each other. It is widely used
because it is cheap and capable of transmitting data quickly, at speeds of 100
megabits per second.
Coaxial
This cabling is not so commonly used as it is more
expensive. It is used where there if lots of interference
that can corrupt data because it has a protective shield
to prevent interference.
Fibre-Optic
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Fibre-optic cable is made up of fine strands of glass that transmit data as
pulses of light.
Fibre-optic cable transmits at very high speeds. It also doesn’t lose data
because of interference and is very secure.
The downside to fibre-optic cabling is that, it is very expensive compared to
twisted pair. You may have heard Virgin Media offering fibre optic broadband
at speed of up to 100Mbps.
Types of Networks
A network is two or more computers connected together.
Networks commonly consist of a server computer that manages the network,
and clients for users to connect to the network. These are known as
client/server networks
Servers are special computers on a network that
manage the running of the network resources;
clients are any computers that can access the
network.
The other kind of network examined in this course is
a peer-to-peer network.
Peer-to-peer networks consist of between two and five
computers connected together. Peer-to-peer networks
don’t have the expense of a dedicated server. All
machines on the network have equal status, with no one
machine having any controlling role. Machines can share
resources such as printers, folders on hard disks and an
internet connection, but security and backups are more
difficult to implement than they would be on a client server
network. This kind of system works best in a home or small office.
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Advantages of Networks
Networks allow users to share data and programs. Data stored on one
computer can be made available to all computers on the network. This saves
time because files do not have to be individually placed on every single
computer on the network. Also, parts of programs can be stored centrally on a
server which saves storage space on the client computers.
Peripherals can be shared more easily on a network. Some expensive
hardware, such as colour laser printers, can be shared using a network.
Instead of buying a printer for each individual workstation one fast printer can
be bought and shared by the clients.
A big advantage of networks is that clients can easily communicate
electronically with other clients on the network.
Peer to Peer V Client/Server
Client Server
Client/Server is a network where there are two levels of computers: servers
and clients.
The server stores and manages access to files and data on a file server.
There may also be a print server which manages printing on the network by
storing a queue of files to be printed.
Advantages
•
•
All data is stored in one central location (easy to backup)
Software is installed once on the file server and then made available to
clients
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•
•
Good security as there can be different level of access rights with each
user
Good for businesses and organisations
Peer to Peer
In a peer to peer network there is no centralised server managing the
network. In this type of network there are a small number of computers of
equal status connected together to share resources such as printers and to
access the files on each others hard discs, or carry out key operations such
as validating users.
Disadvantages
•
•
•
•
Backing up data is difficult as there is no central server where it is
installed in one location
All software has to be installed separately on each individual computer.
Security is difficult to implement as there is no way to centrally control
access to the network
Best used in a trusted environment such as at home.
Local Storage
Backing up locally means to use your own media, such as an external hard
drive or CD, to store extra copies of your data. This is often the most
affordable way to backup large amounts of data.
Advantages
• You have 100% control over the data.
• Very affordable, especially for large amounts of
data. External hard drives come quite cheap these
days.
• No internet connection required.
Disadvantages
• It’s not always very easy or convenient to find
room to store your external media.
• Just like your primary hard drive, external media
can fail as well.
• Possible theft
• No data access on-the-go unless you bring the
media with you which might be too bulky.
However, flash drives may work well.
Cloud Storage
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Cloud storage is quickly gaining popularity with events such as the
introduction of Chrome OS, an operating system that is completely online.
Cloud storage means to store data online. Cloud computing involves
renting computer storage and power from large multinational companies
with special facilities. With cloud computing, the user accesses data
and applications over the internet from their supplier rather than
from the backing storage of the local computer or device that is
currently being used.
The advantages to this are many but include the convenience to the user of
always being able to access their data wherever they are as long as they
have an internet connection and the added security of the user data being
stored safely and securely on a state-of-the-art server.
Advantages
• Some services offer a basic free version, such as Dropbox (2 GB) and
SkyDrive (25 GB)
• Available anywhere there’s an internet connection without having to
carry anything extra
• Third parties handle taking care of the hardware and security so
no worries about storing external media in a safe place
Disadvantages
• Internet connection required. In addition, a relatively fast connection
is recommended for the uploads and downloads to work well.
• Depending on a third party that you have no control over. They can
technically do whatever they want with your files. Be sure to read their
terms and privacy policies.
• The third party might randomly shut down due to
financial hardships or other unforeseen
circumstances.
• Just like your primary hard drive, the hardware third
parties are using can fail at any time.
• Often can be more expensive if you need to store
large amounts of data. Free services usually only offer a maximum of
a few gigabytes.
Watch the video – “What is Cloud Storage”
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Exercise
1. When two computers are linked together it is called:
A
B
C
D
the world wide web
the internet
a server
a network
2. A server controls:
A
B
C
D
switching on a computer
the running of a network
switching off a computer
the running of computers
3. A network with a small geographical spread is called:
A
B
C
D
a LAN
the internet
a WAN
the world wide web
4. Name two advantages of setting up a network.
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5. Name two types of wireless network technology.
6. Name two kinds of network media.
Activity: iTunes, iCloud & Apple
In this activity you are going to be assessed on your knowledge of hardware
and software requirements, storage and connectivity.
1. Open the file “iTunes iCloud Report” from the shared area.
2. Work your way through the questions answering in sentences showing
your understanding.
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