Hardware Basics: Peripherals 3 2001 Prentice Hall3.2 Chapter Outline Input: From Person to Processor Output: From Pulses to People Storage Devices:

Hardware Basics:Hardware Basics:

Peripherals

3

2001 Prentice Hall 3.2

Chapter Outline

• Input: From Person to Processor

• Output: From Pulses to People

• Storage Devices: Input meets Output

• Computer Systems: The Sum of Its Parts

“We swim in a sea of information.”

Gary Snyder


The Omnipresent Keyboard

Keyboards are used to input and manipulate information with keys such as Letters and Numbers…


The Omnipresent Keyboard

…and Cursor Keys that allow you to move around the screen

…Function Keys that send special commands…


Reading Tools

• Optical-mark readers• Bar-code readers

• Magnetic-ink character readers

• Wand readers

• Pen scanners


Scanners

Digitizing the Real World

Audio digitizing andSpeech recognition software

Video digitizing

Sensing devices


Scanners

Scanners capture and digitize images from external paper sources


Video Digitizers

Video digitizers contain circuitry to digitize frames from camcorders and other video sources.


Digital Cameras

Digital cameras turn real-world scenes into digital images that can be stored and manipulated by the computer

The images, stored in memory, can be transferred to a computer for either editing or storage


Audio Digitizers

• Audio digitizers contain circuitry to digitize sounds from microphones and other audio devices.

• Spoken words, music, and sound effects can be captured.


Sound

Video Monitor

ControllingOther Machines

Output: From Pulses to People

Paper


Screen Output

• Video Monitor

– Also called Video Display Terminal (VDT)

– Image exists in video memory—VRAM

– Monitor size is measured diagonally across the screen


• Images are made up ofdots called pixels forpicture elements

Pixels

• The number of pixelsaffects the resolutionof the monitor

• The higher the resolution,the better the image quality


Color Depth (Pixel Depth)

• The amount of information per pixel is known as the color depth

– Monochrome (1 bit of information per pixel)

– Gray-scale (8 bits of information per pixel)

– Color (8 or 16 bits of information per pixel)

– True color (24 or 32 bits of information per pixel)


Examples of Color Depth

1-bit depth

16-bit depth8-bit depth

4-bit depth


CRT (cathode ray tube)

LCD (liquid crystal display)

Classes of Monitors


A CRT is a television-style monitorfeaturing:

CRT (Cathode Ray Tube)

– Clear image

– Quick response time

– Low cost


• LCDs are flat-panel monitors

• Features include:– Lighter weight

– More compact

• More expensive

• Dominate the portable computer market

LCD (Liquid Crystal Display)


Paper Output

• Paper output is sometimes called hard copy

• Hard copy can come from one of two kinds of printers:

– Impact printers

– Nonimpact printers


• Line printers– Used by mainframes for

massive jobs

– Limited characters available

Impact Printers

• Dot-matrix printers– Image formed from dots printed on paper

– Good for text and graphics

– Inexpensive


Nonimpact Printers

• Laser printers

– Image transferred to paper with laser beam

– Faster and more expensivethan dot-matrix

– High-resolution hard copy


Other Nonimpact Printers

• Ink-jet

– Dots of ink are sprayed onto the paper to form the image

– High-resolution hard copy

– Some models print can print colorphotographs


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 tight muscles


Output You Can Hear

• Synthesizers can beused to generate music and sounds

• Many computershave synthesizers

• Sound cards havebuilt-in synthesizers


• Output devices turn bit patterns into non-digital movements

Controlling Other Machines

— Robot arms— Telephone switchboards— Transportation devices— Automated factory

equipment— Spacecraft


Storage Devices:Input Meets Output

• Peripherals with both input and output functions provide semi-permanent storage for data

• Examples include:

– Magnetic tape and disks

– Zip, Jaz and SuperDisks

– Magneto-optical disks


Optical Disks

• Optical disks use laser beams rather than magnets to read and write information

• CD-RW drives can write, erase, and rewrite CDs

• CD-ROM drives are optical drives that read CD-ROMs

• DVD’s can hold between 3.8 and 17 gigabytes of data, they are replacing CD-ROMs


Alternatives

• Flash memory

– Compact alternative

– No moving parts

– May eventually replace disk and tape storage


Ports and Slots…again

• The system board (motherboard) includes several 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


Ports and Slots…again

• Other ports that are generally included on expansion boards instead of the system board:

– Video Port used to plug in a color monitor into the video board

– Microphone, speaker, headphone, MIDI ports used to attach sound equipment

– SCSI port allows several peripherals to be strung together and attached to a single port


Internal and External Drives

• Hard drive

• CD or DVD

• Floppy disk

• Zip Drive

• SCSI port


Expansion Made Easy

• USB and Firewire ports allow multiple devices to be connected to the same port and to be hot swapped:

– 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


Putting It All Together:Networks

• Networks blur the boundaries between computers

– Networks can include hundreds of different computers

– Can span the globe by using satellites and fiber optic cables

Documents

Hardware Basics: Peripherals 3 2001 Prentice Hall3.2 Chapter Outline Input: From Person to Processor Output: From Pulses to People Storage Devices: