Chapter 3:Hardware Basics:Peripherals

Hardware Basics: Peripherals
Chapter 3 Objectives

• List several examples of input devices and explain how they can make it easier to get different types of information into the computer.



• List several examples of output devices and explain the how they make computers more useful.



• Explain why a typical computer has different types of storage devices.



• Diagram how the components of a computer system fit together.
  
  Input: From Person to Processor
  
  
  Keyboard



• The most familiar input device



• Used to enter letters, numbers and special characters



• Standard keyboard



• Ergonomic keyboards



• To address possible medical problems



• Wireless keyboard



• Folding keyboards



• Used with palm-sized computers



• One-handed keyboards



• Keyboards printed on membranes

Pointing Devices

• Mouse



• Touchpad



• Pointing stick



• Trackball



• Joystick



• Graphics tablet



• Touch screen



• Stylus



• Reading Tools



• Read marks representing codes specifically designed for computer input
  



• Optical-mark readers



• Magnetic-ink character readers



• Bar-code readers



• Pen scanners



• Tablet PC



• Smart whiteboard



• Radio Frequency Identification Readers (RFID)
  
  Digitizing the Real World
  


• Scanners capture and digitize printed images.



• Flatbed



• Slide



• Drum



• Sheet-fed
  



• Digital camera



• Snapshots captured as digital images



• Digital images stored as bit patterns on disks or other digital storage media
  



• Video digitizer



• Capture input from a:



• Video camera



• Video cassette recorder or television



• Convert it to a digital signal



• Stored in memory and displayed on computer screens



• Videoconferencing



• People in diverse locations can see and hear each other



• Used to conduct long-distance meetings



• Video images transmitted through networks
  
• Audio digitizers
  
• Digitize sounds from Microphones


• Other input devices
  
• Digital signals can be stored


• A digital signal processing chip compresses the stream of bits before it is transmitted to the CPU.


• Speech recognition software


• Converts voice data into words that can be edited and printed
  
• Sensors


• Designed to monitor physical conditions


• Temperature, humidity, pressure


• Provide data used in:


• Robotics


• Environmental climate control


• Weather forecasting


• Medical monitoring


• Biofeedback
  
• Scientific research
  
  Output: From Pulses to People
  
• Screen Output


• A monitor or video display terminal (VDT) displays characters, graphics, photographic images, animation and video.


• Video adapter—connects the monitor to the computer.


• VRAM or video memory—a special portion of RAM to hold video images.


• The more video memory, the more picture detail is displayed.
  
  Color depth
  1-bit depth
  4-bit depth
  8-bit depth
  16-bit depth
  
• Monitor classes


• CRTs (cathode-ray tubes)


• LCDs (liquid crystal displays)
  • Overhead projection panels
  • Video projectors
  • Portable computers
  


• Paper Output


• Printers produce paper output or hard copy.


• Two basic groups of printers:


• Impact printers
  • Line printers
  • Dot-matrix printers
• Non-impact printers
  • Laser printers


• Laser beam reflected off a rotating drum to create patterns of electrical charges.


• Faster and more expensive than dot matrix printer.


• High-resolution output
  • Inkjet printers


• Sprays ink onto paper to produce printed text and graphic images.


• Prints fewer pages/minute than laser printer .


• High-quality color; costs less than laser printer.


• Multifunction printer or MFP combines a scanner, printer and a fax modem.


• A plotter can produce large, finely scaled engineering blueprints and maps.
  
• Fax Machines and Fax Modems


• Facsimile (fax) machine


• Sending:
  • 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:
  • uses the signals to reconstruct the image
  • prints black-and-white facsimiles or copies of the originals


• Fax modem


• Connect from PC to fax machine via modem and phone line.


• Output You Can Hear


• Sound card


• Enables the PC to:
  • Accept microphone input
  • Play music and other sound through speakers or headphones
  • Process sound in a variety of ways


• Synthesizers


• Used to produce music, noise


• Controlling Other Machines


• Output devices take bit patterns and turn them into non-digital movements.
  


• Robot arms


• Telephone switchboards


• Transportation devices


• Automated factory equipment


• Spacecraft


• Force feedback joystick
  
  Rules of Thumb: Ergonomics and Health
  
  


• Choose equipment that’s ergonomically designed.


• Create a healthy workspace.


• Build flexibility into your work environment.


• Rest your eyes.


• Stretch to loosen tight muscles.


• Listen to your body.


• Seek help when you need it.
  
  Storage Devices: Input Meets Output
  
• Magnetic Tape


• Can store large amounts of information in a small space at a relatively low cost .


• Limitation: sequential data access


• Used mainly for backup purposes


• Magnetic Disks


• Random data access


• Flopy disks


• Provide inexpensive, portable storage


• Hard disks


• Non-removable, rigid disks that spin continuously and rapidly.


• Provide much faster access than a floppy disk


• Removable media (Zip & Jaz disks)


• Provides high-capacity portable storage
  


• Optical Disks


• Use laser beams to read and write bits of information on the disk surface


• Not as fast as magnetic hard disks


• Massive storage capacity


• Very reliable
  
• 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.


• DVD (Digital Versatile Disks)


• Store and distribute all kinds of data


• Hold 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 CDs
• Read-only: 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
• Solid-State Storage Devices
• Flash memory is an erasable memory chip:
• Sizes range from 16 MB to 1 GB
• Compact alternative to disk storage.
• Contains no moving parts.
• Designed for specific applications such as storing pictures in digital cameras.
• Likely to replace disk and tape storage.
  
  Computer Systems: The Sum of Its Parts
  
  Personal Computer Design Classes
• Tower systems
• Tall, narrow boxes, 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.
  
• Laptop computers
• Include all the essential components, including keyboard and pointing device, in one compact box.
  
• Ports and Slots Revisited
• The 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.
  
• Other ports are typically included on expansion boards rather than the system board:
• A video port is used to plug a color monitor into the video board.
• Microphones, speakers, headphones, MIDI ports are used to attach sound equipment.
• An SCSI port allows several peripherals to be strung together and attached to a single port.

• A LAN port uses faster connections to a local-area network (LAN).
• Expansion Made Easy
• With the PC open architecture and the introduction of new interfaces, you can hot swap devices.
• USB (Universal Serial Bus) transmits a hundred times faster than a PC serial port
• Firewire (IEEE 1394) can move data between devices at 400 or more megabits per second. The high speed makes it ideal for data-intensive work, like digital video.
• FireWire 800, which offers 800 Mbps transfer speeds, was recently introduced on high-end Macintosh systems.
  
  
• Putting It All Together
• A typical computer system might have several different input, output, and storage peripherals—the key is compatibility.
• Networks blur the boundaries between computers.
• Networked computers may have access to all the peripherals on a system.
• The computer is, in effect, just a tiny part of a global system of interconnected networks.
  
  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 of the sounds and images of a full-length feature film.
• Tomorrow’s Output
• Flat-panel screens replacing desktop CRTs.
• Retinal displays that work without a screen.
• Tomorrow’s Input: Sensors
• More sophisticated devices will serve as eyes, ears, and other types of sense organs for computer networks.
  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.
• 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, magnetic disks are the most common forms of storage on modern computers.
• Network connections make it possible for computers to communicate with one another directly.