computer hardware

Computer SystemComputer System
HardwareHardware
Input Output Storage

OBJECTIVESOBJECTIVES
 Identify and describe the most common inputIdentify and describe the most common input
devices.devices.
 Identify and describe the most common outputIdentify and describe the most common output
devices.devices.
 Identify and describe storage devices.Identify and describe storage devices.
 Identify and describe how input and outputIdentify and describe how input and output
devices are connected to the computer.devices are connected to the computer.

Input and Output DevicesInput and Output Devices
 Input devices enable a user to input dataInput devices enable a user to input data
and commands to the computer to beand commands to the computer to be
processed.processed.
 Output Devices enable the computer toOutput Devices enable the computer to
give or show you the results of itsgive or show you the results of its
processing.processing.
 Some Devices can perform both input andSome Devices can perform both input and
output operations.output operations.

Input Devices--- The keyboardInput Devices--- The keyboard
 The keyboard is theThe keyboard is the
most widely usedmost widely used
input device.input device.
o As you press key onAs you press key on
the keyboard, anthe keyboard, an
electrical signalelectrical signal
representing that keyrepresenting that key
is sent to computer.is sent to computer.
o Keyboards areKeyboards are
divided into sections.divided into sections.

Input Devices--- The Keyboard (cont.)Input Devices--- The Keyboard (cont.)
 Typewriter Keys: The standard alphabeticTypewriter Keys: The standard alphabetic
and numeric characters you find on aand numeric characters you find on a
typewritertypewriter
 Function Keys: Special keys that performFunction Keys: Special keys that perform
some specific function for the applicationsome specific function for the application
being runbeing run
 Numeric Keypads: used for mathematicalNumeric Keypads: used for mathematical
operationsoperations
 Directional Keys: used to move the cursorDirectional Keys: used to move the cursor
around the screenaround the screen

Input Devices--- The MouseInput Devices--- The Mouse
 The mouse is a pointing device that rollsThe mouse is a pointing device that rolls
around on a flat surface and controls thearound on a flat surface and controls the
location of the pointer on the screen.location of the pointer on the screen.
 The mouse performs the followingThe mouse performs the following
functions:functions:

Pointing:Pointing: Placing the on-screen pointerPlacing the on-screen pointer
at a specific placeat a specific place

Clicking:Clicking: Pressing and releasing thePressing and releasing the
mouse buttonmouse button

Input Devices—The Mouse (cont.)Input Devices—The Mouse (cont.)
 Mouse functions (cont.)Mouse functions (cont.)

Dragging:Dragging: Holding down the mouseHolding down the mouse
button and dragging an object to a newbutton and dragging an object to a new
location by dragging the mouselocation by dragging the mouse

Double-clicking:Double-clicking: Pressing andPressing and
releasing the mouse button twice veryreleasing the mouse button twice very
quicklyquickly

Right-clicking:Right-clicking: Pressing the rightPressing the right
mouse buttonmouse button

Other Pointing DevicesOther Pointing Devices
 Other devices that control the on-screenOther devices that control the on-screen
pointer:pointer:

Trackball:Trackball: This is like a mouse turnedThis is like a mouse turned
upside down. You roll a ball around withupside down. You roll a ball around with
your fingers to control the location of theyour fingers to control the location of the
pointer.pointer.
• These frequently are found onThese frequently are found on
notebook computers.notebook computers.

Other Pointing Devices (cont.)Other Pointing Devices (cont.)

Joystick and wheel:Joystick and wheel: JoysticksJoysticks
consist of a metal or plasticconsist of a metal or plastic
handle mounted on a basehandle mounted on a base
that you can move in anythat you can move in any
direction to move the pointerdirection to move the pointer
or other object.or other object.
• These typically are usedThese typically are used
for video games.for video games.
• Most have buttons that canMost have buttons that can
be pushed or clickedbe pushed or clicked
to control input/output.to control input/output.

Other Input DevicesOther Input Devices
 Pointing stick:Pointing stick: A pressure-sensitiveA pressure-sensitive
device that resembles a pencil eraser;device that resembles a pencil eraser;
found mostly on notebook computersfound mostly on notebook computers
 Graphics tablet:Graphics tablet: A flat drawing surfaceA flat drawing surface
connected to the computerconnected to the computer

The user draws on the surface, and theThe user draws on the surface, and the
figures or writing on the tablet can befigures or writing on the tablet can be
input to the computer for processing.input to the computer for processing.

Other Input Devices (cont.)Other Input Devices (cont.)
 Touch display:Touch display: Screens that containScreens that contain
pictures or shapes that the user canpictures or shapes that the user can
press to input that datapress to input that data
 Stylus/digital pen:Stylus/digital pen: Used with mobileUsed with mobile
devices to input datadevices to input data
 Touchpad:Touchpad: Used mostly inUsed mostly in
laptop/notebook computerslaptop/notebook computers

 Audio/voice input:Audio/voice input: Inputting soundInputting sound
and/or voiceand/or voice

These usually require a microphone andThese usually require a microphone and
special voice recognition software to bespecial voice recognition software to be
installed on the computer.installed on the computer.

 Scanners:Scanners: Devices that can convert aDevices that can convert a
graphical image into a digital image and inputgraphical image into a digital image and input
it to the computerit to the computer

Types of scanners includeTypes of scanners include
• Image scanners for scanning images and textImage scanners for scanning images and text
• Bar code scanners to read product bar codesBar code scanners to read product bar codes
• Magnetic scanners to read the magnetic strip onMagnetic scanners to read the magnetic strip on
a credit carda credit card

 Digital cameras:Digital cameras: Used to take picturesUsed to take pictures
and store them on a magnetic diskand store them on a magnetic disk
instead of on filminstead of on film

Their images can be input directly intoTheir images can be input directly into
the computer.the computer.
 Video input:Video input: Input from a camcorder orInput from a camcorder or
VCR using video capture cardsVCR using video capture cards

BiometricBiometric
input:input: UsesUses
fingerprint,fingerprint,
face,face,
handwriting,handwriting,
and voice forand voice for
identificationidentification

Magnetic Storage DevicesMagnetic Storage Devices
 Floppy disks:Floppy disks: Small, portable disks that hold aSmall, portable disks that hold a
limited amount of datalimited amount of data
 Hard disks:Hard disks: Large-capacity and fast-accessLarge-capacity and fast-access
storage devicesstorage devices
 Zip disks:Zip disks: Auxiliary storage devices that canAuxiliary storage devices that can
hold large quantities of data and can be portablehold large quantities of data and can be portable
 Magnetic tape drives:Magnetic tape drives: Used for making systemUsed for making system
backups and storing large quantities of databackups and storing large quantities of data

Optical Storage DevicesOptical Storage Devices
 CD-DA:CD-DA: Audio CDAudio CD
 CD-R:CD-R: This driveThis drive
allows you to readallows you to read
and to write to aand to write to a
compact diskcompact disk
 CD-ROM:CD-ROM: Can holdCan hold
large amounts oflarge amounts of
data, but is read-data, but is read-
only accessonly access

Optical Storage Devices (cont.)Optical Storage Devices (cont.)
 CD-RW:CD-RW: Can be written on several timesCan be written on several times
 DVD-ROM:DVD-ROM: Read-only DVD formatRead-only DVD format
 DVD-R:DVD-R: Similar to CD, but holds more data;Similar to CD, but holds more data;
read-onlyread-only
 DVD-RW:DVD-RW: Can be written on several timesCan be written on several times
 PhotoCDPhotoCD: Used for storing digital: Used for storing digital
photographs on a CDphotographs on a CD

Solid-State Storage MediaSolid-State Storage Media
 Non-volatile removable mediaNon-volatile removable media
 Miniature mobile mediaMiniature mobile media

Uses integrated circuitsUses integrated circuits
 USB flash driveUSB flash drive

Connects to the computer via aConnects to the computer via a
USB portUSB port

Caring for Storage MediaCaring for Storage Media
 To safeguard your data from damage,To safeguard your data from damage,
follow these tips when dealing withfollow these tips when dealing with
removable media:removable media:

Keep away from magnetic fields.Keep away from magnetic fields.

Avoid extreme temperatures.Avoid extreme temperatures.

Never try to disassemble the case.Never try to disassemble the case.

Remove media from drive when notRemove media from drive when not
being used.being used.

Caring for Storage Media (cont.)Caring for Storage Media (cont.)
 Tips for dealing with storage mediaTips for dealing with storage media
(cont.)(cont.)

Write-protect important data.Write-protect important data.

Hold optical disks at their edges.Hold optical disks at their edges.

Never remove the media from the driveNever remove the media from the drive
if the access light is on.if the access light is on.

Keep disks in a sturdy case whenKeep disks in a sturdy case when
transporting them.transporting them.

Output Devices—MonitorsOutput Devices—Monitors
 MonitorsMonitors are used to display videoare used to display video
output to a user.output to a user.
 Monitors may be monochromatic orMonitors may be monochromatic or
color.color.

Monochromatic monitors display outputMonochromatic monitors display output
in a single-color display.in a single-color display.

Output Devices—Monitors (cont.)Output Devices—Monitors (cont.)
 Factors that influence the quality of aFactors that influence the quality of a
monitormonitor

Screen size: The diagonalScreen size: The diagonal
measurement in inches of the displaymeasurement in inches of the display
areaarea

Resolution: The number of pixels thatResolution: The number of pixels that
can be displayed in the display areacan be displayed in the display area

Dot pitch: The distance between eachDot pitch: The distance between each
pixel in the display areapixel in the display area

Typical Computer MonitorTypical Computer Monitor
Gas
plasma
LCD
This figure shows a typical
computer monitor on a swivel
stand that can be adjusted for
viewing comfort.

Output Devices—PrintersOutput Devices—Printers
 Printers are used to create a hard copyPrinters are used to create a hard copy
of a document or image.of a document or image.

Printers vary by speed, quality, andPrinters vary by speed, quality, and
price.price.

Output Devices—Printers (cont.)Output Devices—Printers (cont.)
 The most popular types of printers areThe most popular types of printers are

Laser:Laser: Produce images using the sameProduce images using the same
techniques as copier machinestechniques as copier machines

Ink jet:Ink jet: Use fine nozzles to spray ink onto theUse fine nozzles to spray ink onto the
page as the paper passes throughpage as the paper passes through

Dot matrix:Dot matrix: Work similarly to a typewriter inWork similarly to a typewriter in
that ink is transferred to the paper by somethat ink is transferred to the paper by some
part of the printer striking a ribbon to transferpart of the printer striking a ribbon to transfer
an imagean image

Laser PrinterLaser Printer
This figure provides an
overview of a laser printer.

Ink Jet PrinterInk Jet Printer
This figure provides an
overview of an ink jet printer.

Other Types of Output DevicesOther Types of Output Devices
 Speakers and headsetsSpeakers and headsets
 Fax machines and fax modemsFax machines and fax modems
 Multifunctional devicesMultifunctional devices

Contain a variation of output optionsContain a variation of output options
 Data projectorsData projectors

Connecting I/O Devices to theConnecting I/O Devices to the
ComputerComputer
 Input and output devices must be connectedInput and output devices must be connected
to the computer before they can be used.to the computer before they can be used.
 Connecting I/O devices to the computer:Connecting I/O devices to the computer:

Plug the device into an existing socket or portPlug the device into an existing socket or port
on the back of the computer.on the back of the computer.

Install an expansion card with the port youInstall an expansion card with the port you
need included on the back of the card.need included on the back of the card.

Connect wirelessly.Connect wirelessly.

SummarySummary
 Input devices enable you to input data andInput devices enable you to input data and
commands into the computer.commands into the computer.
 The most common input devices are theThe most common input devices are the
keyboard and mouse.keyboard and mouse.
 Other types of input devices include trackball,Other types of input devices include trackball,
joystick and wheel, pointing stick, graphicsjoystick and wheel, pointing stick, graphics
tablet, touch display screen, stylus, voicetablet, touch display screen, stylus, voice
recognition devices, touchpad, scanner, digitalrecognition devices, touchpad, scanner, digital
camera, video input, and biometric input.camera, video input, and biometric input.

Summary (cont.)Summary (cont.)
 To maintain a permanent copy of data,To maintain a permanent copy of data,
you should store it on some type ofyou should store it on some type of
storage medium.storage medium.
 The three categories of storage mediaThe three categories of storage media
are magnetic storage, optical storage,are magnetic storage, optical storage,
and solid-state storage.and solid-state storage.
 Monitors and printers are examples ofMonitors and printers are examples of
output devices.output devices.

 Monitors produce soft copy.Monitors produce soft copy.
 Printers are used to produce a paper orPrinters are used to produce a paper or
hard copy of the processed result.hard copy of the processed result.
 Criteria for selecting a printer includeCriteria for selecting a printer include
speed, print quality, and cost.speed, print quality, and cost.
 Input and output devices must beInput and output devices must be
physically connected to the computer.physically connected to the computer.

 Some input devices communicate withSome input devices communicate with
the computer through a physicalthe computer through a physical
connection.connection.
 Wireless devices communicate with theWireless devices communicate with the
computer through infrared or radiocomputer through infrared or radio
waves.waves.

STORAGE DEVICESSTORAGE DEVICES

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