slide 1 computer confluence 7/e chapter 3 hardware basics: peripherals © 2006 prentice-hall, inc
TRANSCRIPT
Slide 2
Computer Confluence 7/e Chapter 3Objectives
Input devices and their roles in getting different types of information into the computer
Output devices and the ways they make computers more useful
The functionality of different types of storage devices
The ways the components of a computer system fit together
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
KeyboardThe most familiar input
deviceUsed to enter letters, numbers
and special characters
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Standard keyboard Ergonomic keyboards
To address possible medical problems Place the keys at an angels that are
easier on your arms and hands.Wireless keyboardFolding keyboards
Used with palm-sized computersOne-handed keyboards Keyboards printed on membranes that can be rolled or folded like paper.
© 2006 Prentice-Hall, Inc.
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this standard-size fabric keyboard rolls up into a lightweight, compact package that can be tucked into a pocket, or briefcase.
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Pointing Devices Mouse
Portable computers :Touchpad (track pad)Pointing stick Trackball
Other pointing devices :Joystick Graphics tablet
stylusTouch screen
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Variants of the Mouse
• Trackballs– Upside down mouse– Hand rests on the ball– User moves the ball– Uses little desk space
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Variants of the Mouse
• Track pads– Stationary pointing
device– Small plastic rectangle– Finger moves across
the pad– Pointer moves with the
pointer– Popular on laptops
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Variants of the MouseTrack point
– Little joystick on the keyboard– Move pointer by moving the joystick
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Devices for the Hand
• Pen based input– Tablet PCs, PDA– Pen used to
write data– Pen used as
a pointer– Handwriting
recognition
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Devices for the hand
• Touch screens– Sensors determine
where finger points– Usually presents a
menu to users– ATM’s, Malls,
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Reading ToolsReads marks
representing codes specifically designed
for computer input
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Optical-mark readers:
use reflected light to determine the location of pencil marks on standardized test answer sheets and similar forms.
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor Magnetic-ink character readers : read those odd-shaped
numbers printed with magnetic ink on the checks. Bar-code readers use light to read universal product code (UPC). They are
attached to point of sale terminals (POS). These terminals send the scanned information to a mainframe computer => item’s price, calculate total.
Radio Frequency Identification Readers : use radio waves to communicate with Radio Frequency
Identification (RFID) tags. When energized by a nearby RFID reader, an RFID tag broadcasts its unique identification number to the reader. which digitizes the information for input into a computer.
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An RFID tag used for
electronic toll collection
• RFID tags used in libraries: square book tag, round CD/DVD tag and rectangular VHS tag.
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Computer Confluence 7/e Chapter 3
Input: From Person to ProcessorBecause test forms, magnetic ink character, bar codes,
and RFID tags were designed to be read by computers, the devices that read them are extremely accurate.
Reading text from books, magazines, and other printed document is more challenging because of the great variety of printed text.
Optical character recognition (OCR) is the technology of recognizing individual characters on a printed page, so they can be stored and edited as text.
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Computer Confluence 7/e Chapter 3
Input: From Person to ProcessorBefore a computer can recognize handwriting or
printed text, it must first create a digital image of the page that it can store in memory.=>scanner.
A scanner doesn’t actually read or recognize letters and numbers on a page- it just makes a digital “ picture” of the page available to the computer.
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Pen scanners :
looks like highlighters.Wireless scanners that can
perform character recognition.
pen-based computers such as the Tablet PC can work without a
keyboard accept input from a stylus handwritten recognition
software to translate the user’s handwritten forms into ASCII characters.
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Personal digital assistants (PDAs): are handheld pen
computers that serve as organizers, notebooks, communication devices, ….
Smart whiteboard: serve as an input device
for a PC. board is stored as a
digital image on the computer’s disk.
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Digitizing devices
• Before a computer can recognize hand-written or printed text, a scanner or other input device must digitize the information- convert it into a digital form-.
• A scanner is an input device that can create a digital representation of a printed image.
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Digitizing the Real World
Scanners capture and digitize printed images
Flatbed Slide scanner : scan only slides and negatives.Drum : larger and more expensive.Sheet-fed : small, portable, and inexpensive.
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Digital cameraSnapshots captured as
digital imagesDigital images stored as
bit patterns on disks or other digital storage media
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Computer Confluence 7/e Chapter 3
Input: From Person to ProcessorVideo digitizer
Capture input from a:Video cameraVideo cassette recorder or television
Convert it to a digital signalStored in memory and displayed on computer screens
Digital video camera can send video signals directly into a computer without a video digitizer.
Videoconferencing People in diverse locations can see and hear each other
Used to conduct long-distance meetings Video images transmitted through networks
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Computer Confluence 7/e Chapter 3
Input: From Person to ProcessorAudio digitizers
Digitize sounds from Microphones Other audio input devices
Digital signals can be Stored Further processed with specialized
software A digital signal processing chip
compresses the stream of bits before it is transmitted to the CPU
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Audiovisual Input Devices
• Microphones– Used to record speech– Speech recognition
• “Understands” human speech• Allows dictation or control of computer• Matches spoken sound to known phonemes• Enters best match into document
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Speech recognition software Converts voice data into words that
can be edited and printed
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Input: From Person to Processor
Sensors Designed to monitor physical conditions
Temperature, humidity, pressure Provide data used in:
Robotics Environmental climate control Weather forecasting Medical monitoring Biofeedback Scientific research
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Output: From Pulses to PeopleScreen Output
A monitor or video display terminal (VDT) displays characters, graphics, photographic images, animation and video
Video adapter —connects the monitor to the computer a circuit board installed in a slot inside the system unit
VRAM or video memory —a special portion of RAM to hold video images the amount of VRAM determines the max. resolution and color depth.the more video memory, the more picture detail is displayed.
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Output: From Pulses to PeopleMonitor size: Measured as a diagonal line across the
screenResolution: The number of pixels displayed on the screen
Pixels (or picture elements): tiny dots that compose a pictureThe higher the resolution, the closer together the dots and the clearer the image.
Image quality is affected by resolution and color depth (or bit depth)
Color depth refers to the number of different colors a monitor displays at one time
© 2006 Prentice-Hall, Inc.
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Monitors
• Categorized by color output– Monochrome
• One color with black background
– Grayscale• black, white, and Varying degrees of gray
– Color• Display 4 to 16 million colors
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Computer Confluence 7/e Chapter 3
Output: From Pulses to PeopleMonitor classes
CRTs (cathode-ray tubes)
LCDs (liquid crystal displays) are now more
popular Overhead projection panels Video projectors Portable computers
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Monitors
• Cathode Ray Tube (CRT)– Electrons fired from the back– Electrons excite phosphor to glow– Phosphor is arranged in dots called pixels
• CRT drawbacks– Very large – Very heavy– Use a lot of electricity
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Flat-panel Monitors• Liquid Crystal Display (LCD)
– Commonly found on laptops– Desktop versions exist– Solve the problems of CRT– Fluorescent lights provide illumination
• Electro-luminescent displays (ELD)– Similar to LCD– Uses phosphor to produce light
• Plasma monitor– Gas is excited to produce light
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Computer Confluence 7/e Chapter 3
Output: From Pulses to People
Paper OutputPrinters produce paper output or hard copy Two basic groups of printers:
Impact printers nonimpact printers
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Commonly Used Printers• Impact printers
Line printers Dot-matrix printers
– Generate output by striking the paper, ribbon, and print hammer together.
– Uses an inked ribbon
• Non-impact printers– Use methods other than force– Tend to be quiet and fast
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Commonly Used Printers
• Line printers
- Impact printer
- speedy but noisy
- limited to printing characters.
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Commonly Used Printers
• Dot matrix printers– Impact printer– Used to print to multi-sheet pages– Print head strikes inked ribbon
– Speed measured in characters per second
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Output: From Pulses to PeopleNon-impact printersLaser printers
Laser beam reflected off a rotating drum to create patterns of electrical charges
Faster and more expensive than dot matrix printer
Produce High-resolution output Color or black and white Print process
– Laser draws text on page– Toner sticks to text– Toner melted to page
Speed measured in pages per minute Quality expressed as dots per inch
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Output: From Pulses to People
Inkjet printers Sprays ink onto paper to produce
printed text and graphic images Prints fewer pages/minute than
laser printer High-quality color costing less than
laser printer Speed measured in pages per
minute Quality expressed as dots per inch
Non-impact printer
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High-Quality Printers
• Photo printers– Produces film quality pictures– Prints very slow– Prints a variety of sizes
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Computer Confluence 7/e Chapter 3
Output: From Pulses to People
Multifunction printer or MFP combines a scanner, printer and a fax modemPlotter: an automated drawing tool that can produce large, finely scaled engineering blueprints and maps
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Output: From Pulses to PeopleFax Machines and Fax ModemsFacsimile (fax) machine
Sending: fax machine scans each page as an image, converts the image into a series of electronic pulses,sends those signals over phone lines to another fax.
Receiving: fax machine uses the signals to reconstruct the image andprint black-and-white facsimiles or copies of the originals
© 2006 Prentice-Hall, Inc.
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Fax Machines and Fax Modems
Fax modem: directly from PC to fax machine via modem & phone
line translate the document into signals that can be sent
over phone wires.Decoded by the receiving fax machine. (remote printer) receive transmission from fax machine (remote
scanner)
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Computer Confluence 7/e Chapter 3
Output: From Pulses to People
Output You Can HearSound card
Enables the PC to:Accept microphone inputPlay music and other sound through speakers or headphonesProcess sound in a variety of ways
Synthesizers Specialized circuitry used to produce music, noise electronically.
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Computer Confluence 7/e Chapter 3
Output: From Pulses to People
Controlling Other Machines
Output devices take bit patterns and turn them into non-digital movements
Robot armsTelephone switchboardsTransportation devicesAutomated factory equipmentSpacecraftForce feedback joystick
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Computer Confluence 7/e Chapter 3
Output: From Pulses to PeopleRules of Thumb: Ergonomics and
Health
Choose equipment that’s ergonomically designedCreate a healthy workspaceBuild flexibility into your work environmentRest your eyesStretch to loosen tight musclesListen to your bodySeek help when you need it
© 2006 Prentice-Hall, Inc.
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Describing Storage Devices
• Store data when computer is off
• Two processes– Writing data– Reading data
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Describing Storage Devices
• Storage terms– Media is the material storing data– Storage devices manage the media– Magnetic devices use a magnet– Optical devices use lasers– Solid-state devices have physical switches
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Magnetic Storage Devices
• Most common form of storage
• Hard drives, floppy drives, tape
• All magnetic drives work the same
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Computer Confluence 7/e Chapter 3
Storage Devices: Input Meets Output
Magnetic TapeCan store large amounts of information in a small space at a relatively low costLimitation: slow sequential data access : retrieve information by zipping through it in the order in which it was recorded. Used mainly for backup purposes
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Storage Devices: Input Meets OutputMagnetic Disks
Random data access information retrieval without regard to the order in which it was recorded.
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Magnetic Storage Devices
• Diskettes– Also known as floppy disks– Read with a disk drive– Provide inexpensive, portable storage– Slow speed.– limited capacity (3 ½ floppy disk holds 1.44
MB)
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Magnetic Storage Devices
• Hard disks– Primary storage device in a computer– Non-removable, rigid disks that spin continuously
and rapidly – 2 or more aluminum platters– Each platter has 2 sides– Provide much faster access than a floppy disk– Data found in 9.5 ms or less– Drive capacity greater than 40 GB
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Magnetic Storage Devices
• Removable high capacity disks– Speed of hard disk– Portability of floppy disk– Several variants have emerged– Ex. Zip disks
• High capacity floppy disk• Stores up to 750 MB of data
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Computer Confluence 7/e Chapter 3
Storage Devices: Input Meets Output
Optical DisksUse laser beams to read and write bits of information on the disk surface
Not as fast as magnetic hard disksMassive storage capacity Very reliable
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Computer Confluence 7/e Chapter 3
Storage Devices: Input Meets Output
CD-ROM Optical drives that read CD-ROMs
CD-R WORM media (write-once, read many)
CD-RW Can read CD-ROMs and write, erase and rewrite data onto CD-R & CD-RW disks
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Computer Confluence 7/e Chapter 3
Storage Devices: Input Meets Output
DVD (Digital Versatile Disks)Store & distribute all kinds of dataHold between 3.8 and 17 gigabytes of information
DVD-ROM drives Can play DVD movies, read DVD data disks, read standard CD-ROMs, and play audio CDsBecause they’re read-only, they can’t record data, music, or movies
DVD-RAM drives Can read, erase, and write data (but not DVD video) on multi-gigabyte DVD-R (but not CD-R or CD-RW) media
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Solid State Devices
• Data is stored physically
• No magnets or laser
• No moving parts
• Very fast
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Computer Confluence 7/e Chapter 3
Storage Devices: Input Meets Output
Solid-State Storage DevicesFlash memory is an erasable memory chip
Sizes range from 16 MB to 1 GBCompact alternative to disk storageContains no moving partsDesigned for specific applications such as storing pictures in digital camerasLikely to replace disk and tape storage
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Storage Devices: Input Meets Output
• USB flash drives Can store up to hundreds of megabytes of
data. they plug into a computer’s USB port.
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Computer Confluence 7/e Chapter 3
Computer Systems: The Sum of Its Parts
Personal Computers: basic design classesTower systems
Tall, narrow boxes that generally have more expansion slots and bays than other designs
Flat desktop systems Designed to sit under the monitor like a platform
All-in-one systems (like the iMac) Combine monitor and system unit into a single housing
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Computer Confluence 7/e Chapter 3
Computer Systems: The Sum of Its Parts
Portable computers Include all the essential components, including keyboard and pointing device, in one compact box
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Extending The Processors Power
• Standard computer ports– Keyboard and mouse ports– USB ports– Parallel– Network– Modem– Audio– Serial– Video
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Computer Confluence 7/e Chapter 3
Computer Systems: The Sum of Its Parts
Ports and Slots RevisitedThe system or motherboard includes several standard ports:
Serial Port for attaching devices that send/receive messages one bit at a time (modems)Parallel Port for attaching devices that send/receive bits in groups (printers)Keyboard/Mouse Port for attaching a keyboard and a mouse
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Extending The Processors Power
• Serial and parallel ports– Connect to printers or modems– Parallel ports move bits simultaneously
• Made of 8 – 32 wires• Internal busses are parallel
– Serial ports move one bit• Lower data flow than parallel• Requires control wires
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Computer Confluence 7/e Chapter 3
Computer Systems: The Sum of Its Parts
Other ports are typically included on expansion boards rather than the system board:
Video Port used to plug in a color monitor into
the video boardMicrophone, speaker, headphone, MIDI ports used to attach sound equipmentLAN port used faster connection to a local-area network (LAN)
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Extending The Processors Power
• SCSI– Small Computer System Interface– Supports dozens of devices– External devices daisy chain
• allows several peripherals to be strung together and attached to a single port
– Fast hard drives and CD-ROMs
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Internal and external drives• Disks drives generally reside in bays
inside the system unit.
• Some PC have extra bays for additional internal hard drives or removable media
• External drives can be connected to the system through ports.
• Some portable enable you to Hot swap devices : remove and replace them without powering down.
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Extending the Processors Power
• Expansion slots and boards– Allows users to configure the machine– Slots allow the addition of new devices– Devices are stored on cards– Computer must be off before inserting
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Computer Confluence 7/e Chapter 3
Computer Systems: The Sum of Its Parts
Expansion Made Easy
With the PC open architecture -the design that enables you to add expansion cards and peripherals-
and the introduction of new interfaces, you can hot swap devices.
© 2006 Prentice-Hall, Inc.
Slide 81
Extending The Processors Power
• USB– Universal Serial Bus– Most popular external bus– Supports up to 127 devices
• including keyboard, mice, digital cameras, scanners, and storage devices can be chained together from a single USB port.
– Hot swappable– transmits a hundred times faster than a PC
serial port
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Extending the Processors Power
• FireWire– IEEE 1394– can move data between devices at 400 or more
megabits per second– High speed makes it ideal for data-intensive work like
digital video Cameras and video equipment– Hot swappable– Port is very expensive
• FireWire 800
- Recently introduced on high-end Macintosh systems
- offers 800 Mbps transfer speeds
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Computer Confluence 7/e Chapter 3
Computer Systems: The Sum of Its Parts
Putting It All TogetherA typical computer system might have several different input, output, and storage peripherals -- the key is compatibilityNetworks blur the boundaries between computersNetworked computers may have access to all the peripherals on a systemThe computer is, in effect, just a tiny part of a global system of interconnected networks
© 2006 Prentice-Hall, Inc.
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Computer Confluence 7/e Chapter 3
Inventing the Future: Tomorrow’s Peripherals Tomorrow’s Storage
Smaller disks that hold more a single-electron memory chip the size of a
thumbnail that can store all the sounds and images of a full-length feature film
Tomorrow’s Output Flat-panel screens are replacing desktop CRTs at
an ever-increasing rate
Retinal display that works without a screen
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You can count how many seeds are in the apple,but not how many apples are in the seed.—Ken Kesey, author of One Flew over the Cuckoo’s Nest
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Computer Confluence 7/e Chapter 3
Inventing the Future: Tomorrow’s Peripherals Tomorrow’s Input: Sensors
More sophisticated devices will serve as eyes, ears, and other types of sense organs for computer networks
© 2006 Prentice-Hall, Inc.
Slide 86
Computer Confluence 7/e Chapter 3
Lesson Summary
Peripherals allow computer to communicate with the outside world and store information for later use information
The most common input devices today are the keyboard and the mouse
A variety of other input devices can be connected to the computer
© 2006 Prentice-Hall, Inc.
A computer terminal is not some clunky old television with a typewriter in front of it. It is an interface where the mind and body can connect with the universe and move bits of it about.—Douglas Adams, author of The Hitchhiker’s Guide to the Galaxy
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Computer Confluence 7/e Chapter 3
Lesson Summary
Output devices perform the opposite function: They accept strings of bits from the computer and transform them into a form that is useful or meaningful outside the computer
Storage devices are capable of two-way communication with the computer: Because of their high-speed random access capability are the most common forms of storage on modern computers
© 2006 Prentice-Hall, Inc.