Chapter Three Hardware Basics: Peripherals

 1999 Addison Wesley Longman3.2 Chapter Outline Input Devices Output Devices Storage Devices Computer Systems: The Sum of Its Parts

 1999 Addison Wesley Longman3.3 Input: From Person to Processor Person Input Device Processor

 1999 Addison Wesley Longman3.4 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 Longman3.5 Mouse Trackball Joystick Graphics Tablet Touch Screen Pointing Devices

 1999 Addison Wesley Longman3.6 Reading Tools Optical-mark readers Bar-code readers Magnetic-ink character readers Wand readers

 1999 Addison Wesley Longman3.7 Audio digitizing Video digitizing Flatbed Scanner Hand-held Scanner Digitizing the Real World

 1999 Addison Wesley Longman3.8 Audio Digitizers Audio digitizers contain circuitry to digitize sounds from microphones and other audio devices.

 1999 Addison Wesley Longman3.9 Video Digitizers Video digitizers contain circuitry to digitize frames from camcorders and other video sources.

 1999 Addison Wesley Longman3.10 Scanners Scanners capture and digitize images from external paper sources.

 1999 Addison Wesley Longman3.11 Video Monitor Sound Controlling Other Machines Output: From Pulses to People Paper

 1999 Addison Wesley Longman3.12 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 Longman3.13 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 Longman3.14 Images are made up of dots called pixels for picture elements The number of pixels affects the resolution of the monitor The higher the resolution, the better the image quality Pixels

 1999 Addison Wesley Longman3.15 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 Longman3.16 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 Longman3.17 Examples of Color Depth 1-bit depth 4-bit depth 8-bit depth 16-bit depth

 1999 Addison Wesley Longman3.18 CRT (cathode ray tube) LCD (liquid crystal display) Classes of Monitors

 1999 Addison Wesley Longman3.19 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 Longman3.20 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 Longman3.21 Characters letters (5*7 dot matrix) Chinese characters –16 * 16 （可辨認） –24 * 24 （清晰） –32 * –64 * 64 （美觀）

 1999 Addison Wesley Longman3.22 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 Longman3.23 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 Longman3.24 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 Longman3.25 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 Longman3.26 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 color photographs

 1999 Addison Wesley Longman3.27 Other Non-impact Printers Plotters –Image transferred to paper with ink pens –Very high resolution –Excellent for scientific and engineering applications

 1999 Addison Wesley Longman3.28 Output You Can Hear Synthesizers can be used to generate music and sounds Many computers have synthesizers Sound cards have built-in synthesizers

 1999 Addison Wesley Longman3.29 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 Longman3.30 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 Longman3.31 Magnetic Tape Magnetic tape is a common form of storage for mainframe computers. Information is accessed sequentially Massive storage for low cost but retrieval is slow

 1999 Addison Wesley Longman3.32 Magnetic Tape backup storage 7 or 9 tracks 2400 ft 800, 1600, 6400 bpi blocked 70GB, 200GB

 1999 Addison Wesley Longman3.33 Hard Disks Magnetic Disks Floppy Disk Zip Disks and Zip Drive

 1999 Addison Wesley Longman3.34 Magnetic Disk semi-random access –access time seek time latency time data transfer time

 1999 Addison Wesley Longman3.35 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 Longman3.36 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 Longman3.37 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 Longman3.38 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 Longman3.39 Optical Disk CD-ROM (compact disk ROM) –about 600 MB –can be created on PC (CD-R, WORM) –rewritable optical disk (CD-RW)

 1999 Addison Wesley Longman3.40 Storage Capacity A single CD-ROM can hold as much information as K diskettes 500 books (text only)