Chapter Three Hardware Basics: Peripherals 1999 Addison Wesley Longman3.2 Chapter Outline Input...
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Transcript of Chapter Three Hardware Basics: Peripherals 1999 Addison Wesley Longman3.2 Chapter Outline Input...
1999 Addison Wesley Longman 3.2
Chapter Outline
• Input Devices
• Output Devices
• Storage Devices
• Computer Systems: The Sum of Its Parts
1999 Addison Wesley Longman 3.4
The Omnipresent Keyboard
Do you know where these keys are located on the keyboard and how to use them?
Letters, Numbers, Cursor Keys, Delete Key, Enter (Return) Key, and Function Keys
1999 Addison Wesley Longman 3.5
Mouse
Trackball
Joystick
Graphics Tablet
Touch Screen
Pointing Devices
1999 Addison Wesley Longman 3.6
Reading Tools
• Optical-mark readers
• Bar-code readers
• Magnetic-ink character readers
• Wand readers
1999 Addison Wesley Longman 3.7
Audio digitizing
Video digitizing
Flatbed Scanner
Hand-held Scanner
Digitizing the Real World
1999 Addison Wesley Longman 3.8
Audio Digitizers
Audio digitizers contain circuitry to digitize sounds from microphones and other audio devices.
1999 Addison Wesley Longman 3.9
Video Digitizers
Video digitizers contain circuitry to digitize frames from camcorders and other video sources.
1999 Addison Wesley Longman 3.10
Scanners
Scanners capture and digitize images from external paper sources.
1999 Addison Wesley Longman 3.11
Video Monitor
Sound
ControllingOther Machines
Output: From Pulses to People
Paper
1999 Addison Wesley Longman 3.12
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.
1999 Addison Wesley Longman 3.13
Screen Output
• Video Monitor– Also called Video
Display Terminal (VDT)
– Image exists in video memory—VRAM
– Monitor size is measured diagonally across the screen
1999 Addison Wesley Longman 3.14
• Images are made up ofdots called pixels forpicture elements
• The number of pixelsaffects the resolutionof the monitor
• The higher the resolution,the better the image quality
Pixels
1999 Addison Wesley Longman 3.15
Raster Graphics
• arrangement of pixels into rows & columns• character mode (25*80)• graphics mode (350*720)• higher resolution (600*800, 768*1024)
1999 Addison Wesley Longman 3.16
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)
1999 Addison Wesley Longman 3.17
Examples of Color Depth
1-bit depth 4-bit depth
8-bit depth 16-bit depth
1999 Addison Wesley Longman 3.18
CRT (cathode ray tube)
LCD (liquid crystal display)
Classes of Monitors
1999 Addison Wesley Longman 3.19
• A CRT is a television-style monitor
• Its features include:– Clear image– Quick response time– Low cost– Very popular
CRT (Cathode Ray Tube)
1999 Addison Wesley Longman 3.20
• LCDs comprise flat-panel monitors
• Features of flat-panel monitors include:– Lighter weight– More compact– More expensive– Dominate the portable
computer market
LCD (Liquid Crystal Display)
1999 Addison Wesley Longman 3.21
Characters
• letters (5*7 dot matrix)
• Chinese characters– 16 * 16 (可辨認)– 24 * 24 (清晰)– 32 * 32 ...– 64 * 64 (美觀)
1999 Addison Wesley Longman 3.22
Paper Output
• Paper output is sometimes called hard copy
• Hard copy can come from one of two kinds of printers:– Impact printers– Non-impact printers
1999 Addison Wesley Longman 3.23
Printer
• impact printers - noisy, non-graphic– character printer
– line printer
– dot matrix printer
• non-impact printers– thermal-wax-transfer printer
– ink-jet printer
– laser printer
1999 Addison Wesley Longman 3.24
• Line printers– Used by mainframes for
massive jobs– Limited characters available
• Dot-matrix printers– Image formed from dots printed on paper– Good for text and graphics– Inexpensive
Impact Printers
1999 Addison Wesley Longman 3.25
Non-impact Printers
• Laser printers– Image transferred to paper with
laser beam– Faster and more expensive
than dot-matrix– High-resolution hard copy
1999 Addison Wesley Longman 3.26
Non-impact 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
1999 Addison Wesley Longman 3.27
Other Non-impact Printers
• Plotters– Image transferred to paper with ink pens– Very high resolution– Excellent for scientific and engineering
applications
1999 Addison Wesley Longman 3.28
Output You Can Hear
• Synthesizers can beused to generate music and sounds
• Many computershave synthesizers
• Sound cards havebuilt-in synthesizers
1999 Addison Wesley Longman 3.29
• By turning bit information into movements (robots) or measurements (sensors), machines can control other machines:– Automated factory equipment– Telephone switchboards– Robot arms– Spacecraft
Machines Controlling Other Machines
1999 Addison Wesley Longman 3.30
Secondary Storage:Input and Output
• Peripherals with both input and output functions. This form of storage is semi-permanent
• Examples include:– Magnetic tape– Magnetic disks– Optical disks
1999 Addison Wesley Longman 3.31
Magnetic Tape
• Magnetic tape is a common form of storage for mainframe computers.
• Information is accessedsequentially
• Massive storage for lowcost but retrieval is slow
1999 Addison Wesley Longman 3.32
Magnetic Tape
• backup storage
• 7 or 9 tracks
• 2400 ft
• 800, 1600, 6400 bpi
• blocked
• 70GB, 200GB
1999 Addison Wesley Longman 3.34
Magnetic Disk
• semi-random access– access time
• seek time• latency time• data transfer time
1999 Addison Wesley Longman 3.35
Hard Disks
• Hard disks are:– Rigid, magnetically sensitive metal disks.– Designed so that information can be
randomly accessed– Designed for large storage capacity– Able to access data quickly– Not removable from the drive
1999 Addison Wesley Longman 3.36
• Diskettes are:– Flexible, magnetically sensitive plastic
disks– Information can be randomly accessed.– Has limited storage capacity– Access of data not as quick
as hard disks– Removable from the drive
Diskettes
1999 Addison Wesley Longman 3.37
Magnetic Disk (II)
• floppy disk– 8, 5 3/4, 3 1/2 inch (1.44M)– movable read/write head– track, sector
• hard disk– faster, larger (8.4G, 12G, 30G)– cylinder, track, sector
1999 Addison Wesley Longman 3.38
Optical Disks
• CD-ROM and magneto-optical disks provide:– Random access of information– A high storage capacity– Have an access time that varies but is
slower than hard disks– Are removable from the drive
1999 Addison Wesley Longman 3.39
Optical Disk
• CD-ROM (compact disk ROM)– about 600 MB– can be created on PC (CD-R, WORM)– rewritable optical disk (CD-RW)