Download IC3 Basics, Internet and Computing Core Certification

Unit 1 — Computer Basics
Objectives
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Identify and describe the most common
input devices.
Identify and describe the most common
output devices.
Identify and describe how input and output
devices are connected to the computer.
Lesson 5 – Input, Output, Storage and Networks
Objectives (continued
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Identify and describe storage devices.
List and describe the types of networks.
Describe the different network topologies.
Describe network architecture and
protocols.
Lesson 5 – Input, Output, Storage and Networks
Input and Output Devices
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Input devices enable a user to input data
and commands to the computer to be
processed.
Output devices enable the computer to give
or show you the results of its processing.
Some devices can perform both input and
output operations.
Lesson 5 – Input, Output, Storage and Networks
Input Devices – The Keyboard
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The keyboard is the most common input device.
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As you press keys on the keyboard, an electrical signal
representing that key is sent to the computer.
Keyboards are divided into sections:
 Typewriter keys: The standard alphabetic and numeric
characters you would find on a typewriter.
 Function keys: Special keys that perform some specific
function for the application being run.
 Numeric keypad: Used for mathematical operations.
 Directional keys: Used to move the cursor around the
screen.
Lesson 5 – Input, Output, Storage and Networks
Input Devices – The Mouse
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The mouse is a pointing device that rolls around on a flat
surface and controls the location of the pointer on the
screen.
The mouse performs the following functions:
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Pointing: Place the on-screen pointer at a specific place.
Clicking: Press and release the mouse button.
Dragging: Holding down the mouse button and dragging an
object to a new location by dragging the mouse.
Double-clicking: Pressing and releasing the mouse button
twice very quickly.
Right-clicking: Pressing the right mouse button.
Lesson 5 – Input, Output, Storage and Networks
Other Pointing Devices
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In addition to the mouse, there are other devices that
control the on-screen pointer, including a
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Joystick: Joysticks consist of a metal or plastic handle
mounted on a base that you can move in any direction to
move the pointer or other object.
 These are typically used for video games.
 They frequently have buttons that can be pushed or
clicked to control input/output.
Trackball: This is like a mouse turned upside down. You roll
a ball around with your fingers to control the location of the
pointer.
 These are frequently found on notebook computers.
Lesson 5 – Input, Output, Storage and Networks
Other Input Devices (Part I)
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A graphic tablet is a flat drawing surface connected to the
computer.
– The user draws on the surface, and the figures or writing on
the tablet can be input to the computer for processing.
Touch display screens contain pictures or shapes that the
user can press to input that information.
Voice recognition devices allow a user to speak to a computer
and have their words input to an application program.
– These usually require a microphone and special voice
recognition software to be installed on the computer.
Lesson 5 – Input, Output, Storage and Networks
Other Input Devices (Part II)
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Scanners are devices that can convert a graphical image
into a digital image and input it to the computer.
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Types of scanners include
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Video input from a camcorder or VCR can be input using
video capture cards.
Digital cameras take pictures and store them on a magnetic
disk instead of on film.
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Image scanners for scanning images and text.
Bar code scanners to read product bar codes.
Magnetic scanners to read the magnetic strip on a credit
card.
Their images can be input directly into the computer.
Lesson 5 – Input, Output, Storage and Networks
Output Devices - Monitors
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Monitors are used to display video output to a user.
Monitors may be monochromatic or color.
– Monochromatic monitors display output in a single-color
display.
Factors that influence the quality of a monitor are
– Screen size: The diagonal measurement in inches of the
display area.
– Resolution: The number of pixels that can be displayed in
the display area.
– Dot pitch: The distance between each pixel in the display
area.
Lesson 5 – Input, Output, Storage and Networks
Typical Computer Monitor
This figure shows a typical
computer monitor on a swivel
stand that can be adjusted for
viewing comfort. A few years ago,
monitors with a diagonal measurement of 13” were standard on
computer systems, but today 15”,
17”, 19”, and even larger screens
are becoming the norm. Notebook
computers usually use a flat-panel
display built into the lid of the
notebook case.
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Lesson 5 – Input, Output, Storage and Networks
Output Devices - Printers
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Printers are used to create a hard copy of a document or
image.
– Printers vary by speed, quality, and price.
The most popular types of printers are
– Laser: Produce images using the same techniques as
copier machines.
– Ink-Jet: These use fine nozzles to spray ink onto the page
as the paper passes through.
– Dot matrix: These work similarly to a typewriter in that ink
is transferred to the paper by some part of the printer
striking a ribbon to transfer an image.
Lesson 5 – Input, Output, Storage and Networks
Laser Printer
Operation
This figure provides an
overview of how a laser
printer works.
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Lesson 5 – Input, Output, Storage and Networks
Ink-Jet
Operation
This figure shows how
an ink-jet printer works.
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Lesson 5 – Input, Output, Storage and Networks
Connecting I/O Devices to the
Computer
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Input and output devices must be connected to
the printer before they can be used.
There are two ways to connect I/O devices to
the computer:
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Plug the device into an existing socket or port on
the back of the computer.
Install an expansion card with the port you need
included on the back of the card.
Lesson 5 – Input, Output, Storage and Networks
Serial, Parallel, and Special Ports
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Serial ports transmit data one bit at a time and are
used to connect a mouse, modem, and keyboard.
Parallel ports transmit data 8 bits at a time and are
used for printers and external storage devices.
There are also special ports:
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SCSI: This port can allow many devices to use a single port.
MIDI: Used to connect recording devices.
PC card: Can be connected to add memory or storage
capacity.
USB: Can be used to replace serial and parallel ports and
can handle up to 127 devices.
Lesson 5 – Input, Output, Storage and Networks
Storage Devices - Magnetic
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There are many types of magnetic storage devices,
including
– Floppy disks: Small, portable disks that hold a limited
amount of data.
– Hard disks: Large-capacity and fast-access storage
devices.
– Zip and Jaz drives: Auxiliary storage devices that can
hold large quantities of data and can be portable.
– Magnetic tape drives: Used for making system
backups and storing large quantities of data.
Lesson 5 – Input, Output, Storage and Networks
Optical Storage Devices
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There are several optical storage devices in use today,
including
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CD-ROM: Can hold large amounts of data, but is read-only
access.
CD-R: This drive allows you to read and to write to a
compact disk.
WORM disks: Used for permanently storing large amounts
of data.
Photo-CD: Used for storing digital photographs on a CD.
DVD: This is the size of a CD, but can hold much more
data, including full-size movies.
Lesson 5 – Input, Output, Storage and Networks
Caring for Removable Storage
Media
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To safeguard your data from damage, follow these tips when
dealing with removable media:
– Keep away from magnetic fields.
– Avoid extreme temperatures.
– Never try to disassemble the case.
– Remove media from drive when not being used.
– Write-protect important data.
– Hold optical disks at their edges.
– Never remove the media from the drive if the access light is
on.
– Keep disks in a sturdy case when transporting them.
Lesson 5 – Input, Output, Storage and Networks
Introducing Networks
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A network is a group of two or more computers linked together.
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Most networks have a server which manages the network
resources.
Most networks have multiple clients, which are computers that
access the server.
A network confined to a limited geographical area is called a
local area network (LAN).
A network spread over a wide area is called a wide area
network (WAN).
The transmission of data from one location to another is called
data communications.
Lesson 5 – Input, Output, Storage and Networks
Data Communications
This figure shows the
main components
required for data
communications: A
sending device, a
receiving device, a
communication path
or channel, a device to
convert the signal so
that the channel can
carry it, and the software to send and
receive messages.
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Lesson 5 – Input, Output, Storage and Networks
Network Benefits
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Networks provide almost instant
communication with other users on the
network.
Users can share information.
Users can share hardware.
Users can share software.
Users can work on group projects.
Lesson 5 – Input, Output, Storage and Networks
Communications Media
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Sending data from one computer to another requires
a channel, the link through which the message is
sent.
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A phone line or cable is a channel.
You need a device on each end of the channel to
convert the computer signal to a signal type that the
channel can send.
Sending a message through the channel requires a
transmission media, which can be physical or
wireless.
Lesson 5 – Input, Output, Storage and Networks
Physical Media
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Physical media types include
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Wireless media types include
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Twisted-pair cable
Coaxial cable
Fiber optic cable
Radio signals
Microwaves
Satellites
Lesson 5 – Input, Output, Storage and Networks
Physical Media Examples
Coaxial
Twisted pair
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Lesson 5 – Input, Output, Storage and Networks
Fiber optic
Wireless Media Examples
Microwaves
Satellites
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Lesson 5 – Input, Output, Storage and Networks
Network Hardware
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Most networks consist of a server and multiple client
computers.
They also include two other categories of hardware:
– Communications hardware
These devices facilitate the transmitting and receiving
of data.
Network transmission hardware
 These devices connect the cabling and amplify
signals as they travel across the network.
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Lesson 5 – Input, Output, Storage and Networks
Communications Hardware
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Modems: Convert analog signals to digital and vice
versa.
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Cable modems: Use coaxial cable to send data over
cable TV lines.
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Modems enable a computer to send data over a standard
phone line.
The sending computer and the receiving computer must both
have modems.
These have much faster transmission rates than a standard
telephone line modem.
Lesson 5 – Input, Output, Storage and Networks
Network Transmission Hardware
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Network Interface Cards (NICs)
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Hub
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Links networks using different protocols
Router
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Connects one LAN to another LAN
Gateway
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Receives and sends signals back out
Bridge
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All PCs in a LAN must have a NIC.
Connects multiple networks and determines the fastest route for
sending data over the network
Lesson 5 – Input, Output, Storage and Networks
Types of Networks
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Local area networks (LANs) are usually confined to a
limited area.
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The two most popular LANs are
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Wide area networks (WANs) are spread across a city,
a state, the country, or the world.
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Client/server
Peer-to-peer
Most WANs consist of two or more LANs connected by
routers.
Some WANs may be configured as intranets or extranets.
Lesson 5 – Input, Output, Storage and Networks
Client/Server vs. Peer-to-Peer
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Lesson 5 – Input, Output, Storage and Networks
Network Topologies
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A topology is the geometric arrangement of
the network.
The most common topologies are
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Bus: All devices are connected to a master cable.
Ring: Similar to a bus except that the devices are
connected in a circle.
Star: All devices are connected to a central hub or
computer.
Lesson 5 – Input, Output, Storage and Networks
Example of Bus Topology
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Lesson 5 – Input, Output, Storage and Networks
Example of Ring Topology
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Lesson 5 – Input, Output, Storage and Networks
Example of Star Topology
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Lesson 5 – Input, Output, Storage and Networks
Communications Protocols
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A protocol is a set of rules that allows computers to
exchange data.
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The protocol determines
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The most common protocols are
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How a sending device indicates it has finished sending.
How a receiving device indicates the message was
received.
The type of error checking to use.
Ethernet: Most common LAN protocol.
Token ring: Also used on LANs.
TCP/IP: Used on the Internet.
Lesson 5 – Input, Output, Storage and Networks
Network Operating Systems
Software
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Networks require a network operating system (NOS)
and a desktop operating system.
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The NOS runs on the server and provides
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The clients run the desktop OS.
Network administration tools
Print services
Client services
Security services
Lesson 5 – Input, Output, Storage and Networks
Summary
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The most common input devices are the keyboard
and mouse.
The keyboard is divided into four sections:
alphabetical keys, function keys, cursor keys, and
the numeric keypad.
Additional special-purpose keys perform
specialized functions.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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The mouse is a pointing device used to input data.
Input devices enable you to input data and
commands into the computer.
Other types of input devices include joysticks,
trackballs, graphic tablets, touch display screens,
voice recognition devices, scanners, and electronic
pens.
Printers are used to produce a paper or hard copy of
the processed result.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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Criteria for selecting a printer include speed, print
quality, and cost.
Printers are classified as either impact or nonimpact.
The most popular types of printers are laser, inkjet, and dot matrix.
Input and output devices must be physically
connected to the computer.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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There are two ways to connect I/O devices to a
computer: Plug the device into a port in the back of the
computer or install a circuit board with the needed port
included.
There are several types of ports: USB, SCSI, MIDI,
parallel, and serial.
To maintain a permanent copy of data, you must store
it on some type of storage medium. These may
include floppy diskettes, hard drives, CDs, magnetic
tape cartridges, and WORM disks.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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A network is a group of two or more computers linked
together.
A local area network is generally confined to a limited
geographical area.
A wide area network is made up of several connected
local area networks.
Data communications is the transmission of data from
one location to another.
The Internet is the biggest network of all.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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You can use a network for information sharing,
hardware or software sharing, and as a collaborative
environment.
The link through which data is transmitted is the
communications channel.
Transmission media can be either physical or
wireless.
Physical media includes twisted-pair cable, coaxial
cable, and fiber optic cable.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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Wireless media includes radio signals, microwaves, and
satellites.
Most networks consist of a network server and computer
clients.
A modem is a type of communications device.
Network interface cards enable the sending and receiving
of data between the PCs in a LAN.
A hub is a device that controls the incoming and
forwarding of data.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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A gateway links two different types of networks.
A router directs the Internet or LAN traffic.
The two popular types of LANs are the client/
server network and peer-to-peer.
Network topologies include bus, ring, and star.
A protocol is an agreed-on set of rules and
procedures for transmitting data between two or
more devices.
Lesson 5 – Input, Output, Storage and Networks
Summary (continued)
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The Ethernet is one of the most popular LAN
protocols.
Token ring is the second most widely used LAN
protocol.
TCP/IP is a protocol used by both LANs and
WANs to connect to the Internet.
All computers require an operating system.
Networks require network operating systems.
Lesson 5 – Input, Output, Storage and Networks