Chapter 3 Hardware Basics Peripherals 2002 Prentice Hall

Chapter 3 Hardware Basics: Peripherals 2002 Prentice Hall

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, poet 2002 Prentice Hall 2

Input: From Person to Processor 2002 Prentice Hall 3

The Keyboard The most common input device is the keyboard, which is used to enter letters, numbers and special characters. 2002 Prentice Hall 4

Working with the Keyboard • Function keys are special purpose keys whose function depends on the software being used. • Cursor keys are used to move the cursor up, down, left, or right. 2002 Prentice Hall 5

Variations on Keyboard Design Ergonomic § to address repetitive stress injuries Wireless Folding Half 2002 Prentice Hall 6

Pointing Devices 2002 Prentice Hall 7

Reading Tools Input devices “read” directly from paper and convert printed information into bit patterns that can be processed by the computer. § § § Optical-mark readers Bar-code readers Magnetic-ink character readers Wand readers Pen scanners 2002 Prentice Hall 8

Digitizing the Real World Scanner Digital camera Speech recognition Sensing devices Audio and video digitizers 2002 Prentice Hall 9

Scanners capture and digitize printed images. There are several types of scanners: § Flatbed scanners § Handheld scanners § Sheet-fed scanners 2002 Prentice Hall 10

Digital Cameras Digital cameras capture snapshots and store them as bit patterns on disks or other storage media. 2002 Prentice Hall 11

Video Digitizers Video digitizers capture input from video sources such as video camera and convert it to a digital signal that can be stored in memory and displayed on a computer screen. 2002 Prentice Hall 12

Audio Digitizers Audio digitizers capture spoken words, music and sound effects and convert them to digitized sounds. These sounds can be stored in a computer’s memory and modified with computer software. 2002 Prentice Hall 13

Sensing Devices Sensing devices are used to monitor temperature, humidity, pressure and other physical quantities. The data collected provides data for use in robotics, environmental climate control, weather forecasting and other applications. 2002 Prentice Hall 14

Output: From Pulses to People Screen Output Paper Output Sound Output Controlling Other Machines 2002 Prentice Hall 15

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 detail of a picture displayed) 2002 Prentice Hall 16

Screen Talk Monitor size - measured as a diagonal line across the screen. Pixels (or picture element) - tiny dots that compose a picture Resolution - the number of pixels displayed on the screen (the higher the resolution, the closer together the dots) 2002 Prentice Hall 17

Image Quality 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 the same time 2002 Prentice Hall 18

Examples of Color Depth 1 -bit depth 4 -bit depth 8 -bit depth 16 -bit depth 2002 Prentice Hall 19

Monitor Classes CRT (cathode ray tube) 2002 Prentice Hall LCD (liquid crystal display) 20

Cathode Ray Tube (CRT) The cathode ray tube has the following characteristics: § Low cost § Speedy response time § Clear image 2002 Prentice Hall 21

Liquid Crystal Display (LCD) Light-weight Compact Flat-panel Used in overhead projection panels and video projectors to project computer images More expensive than CRTs Increasingly being seen with desktop computers 2002 Prentice Hall 22

Paper Output Printers produce paper output or hard copy 2 kinds of printers: § Impact printers § Non-impact printers 2002 Prentice Hall 23

Impact Printers Line printer § Used by mainframes to produce massive printouts § Limited to printing characters Dot matrix printer § Images created by a matrix of tiny dots § Low print quality § Low cost 2002 Prentice Hall 24

Non-impact Printers Laser Printer § A laser beam reflected off a rotating drum to create patterns of electrical charges § Faster and more expensive than dot matrix printer § High-resolution output 2002 Prentice Hall 25

More on Non-impact Printers Ink-jet Printer § 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 2002 Prentice Hall 26

Additional Output Devices Multifunction peripheral or MFP combines a scanner, printer and a fax modem. A plotter is an automated drawing tool that can produce large, finely scaled engineering blueprints and maps. 2002 Prentice Hall 27

Output You Can Hear A sound card allows the PC to accept microphone input, play music and other sounds through speakers or headphones. Synthesizers are included in sound cards and have specialized circuitry designed to generate sounds electronically. 2002 Prentice Hall 28

Controlling Other Machines Output devices take bit patterns and turn them into nondigital movements. § § § Robot arms Telephone switchboards Transportation devices Automated factory equipment Spacecraft Digiscents 2002 Prentice Hall 29

Rules of Thumb: Ergonomics & 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 2002 Prentice Hall 30

Storage Devices: Input Meets Output Secondary storage devices are computer peripherals capable of performing both input and output functions Information is stored semi-permanently on tape and disk drives Examples of storage devices § Magnetic tapes and disks § Zip, Jaz and Super. Disks § Optical disks 2002 Prentice Hall 31

Magnetic Media Magnetic tapes § Sequential access § Can store large amounts of information in a small space at a relatively low cost § Limitation: sequential access § Used mainly for backup purposes 2002 Prentice Hall 32

Magnetic Media Magnetic drives § Random access § Floppy disks for inexpensive, portable storage § Hard disks are non-removable, rigid disks that spin continuously and rapidly thus providing much faster access than a floppy disk. § Removable media (Zip & Jaz disks) provide high-capacity portable storage. 2002 Prentice Hall 33

Optical Media Optical disk drive uses laser beams to read and write bits of information on the disk surface. § Not as fast as magnetic hard disks § Massive storage capacity and reliability 2002 Prentice Hall 34

Types of Optical Media CD-ROM drives are optical drives that read CD-ROMs. CD-R are 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 & distribute all kinds of data. They hold between 3. 8 and 17 gigabytes of information. 2002 Prentice Hall 35

Solid-state Storage Devices Flash memory is an erasable memory chip. § Compact alternative § No moving parts § Designed for specific applications such as storing pictures in digital cameras § Likely to replace disk and tape storage 2002 Prentice Hall 36

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 2002 Prentice Hall 37

More on Ports and Slots 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 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 2002 Prentice Hall 38

Internal and External Drives Hard drive § Bays § Hot swapping CD or DVD Floppy disk Zip Drive SCSI port 2002 Prentice Hall 39

Expansion Made Easy With the open architecture of the PC 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 – high speed makes it ideal for data-intensive work like digital video 2002 Prentice Hall 40

Putting It All Together with Networks 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. b 2002 Prentice Hall 41

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