The Keyboard

1
The Keyboard

• How is the keyboard divided?

• Typing area
• Numeric keypad
• Function keys

Click to view Web Link then click Keyboards
p. 5.4 Fig. 5-3
2
Display Devices

• What is a CRT monitor?

• Large sealed, glass screen
• Screen coated with tiny dots of phosphor material
• Pixel, or picture element, is single point in
  electronic image
• Three dots (red, blue, and green) combine to make
  up each pixel

p. 6.5 Fig. 6-3
3
Display Devices

• What are typical sizes for CRT monitors?

• 15, 17, 19, 21, and 22 inch screen size
• Viewable size is diagonal measurement of actual
  viewing area provided by the monitor

p. 6.5
4
Display Devices

• What is a liquid crystal display (LCD) monitor?

• Type of flat-panel display
• Uses liquid crystals between two sheets of
  material to present information on screen
• Electric current passes through crystals, which
  creates images on the screen

p. 6.5 Fig. 6-4
5
Display Devices

• Where are some features of LCD screens?

• Lightweight and compact
• Consumes less than one-third of the power than
  does a CRT monitor
• Ideal for notebook and handheld computers

p. 6.6 Fig. 6-5
6
Display Devices

• What is a Web-enabled device?

• Allows access to the Web or e-mail
• Cellular telephones
• Pagers
• Many use monochrome LCD displays to save battery
  power

Click to view Web Link then click Web-enabled
Devices
p. 6.6 Fig. 6-6
7
Display Devices

• What is an electronic book (e-book) ?

• Small, book-sized computer that uses an LCD
  screen
• Allows users to read, save, highlight, bookmark,
  and add notes to online text
• Download new book contentfrom Web

p. 6.7 Fig. 6-7
8
Display Devices

• What are the two technologies used for LCD
  monitors?

p. 6.8
9
Display Devices

• What is a gas plasma monitor?

• Flat-panel display uses layer of gas plasma
  between two sheets of material

• Larger screen sizes and higher display quality
  than LCD, but much more expensive

p. 6.8 Fig. 6-8
10
Display Devices

• What is display resolution?

• Describes the sharpness and clarity of image
• The higher the resolution, the sharper the image
  and the more that can display on the monitor

Total of 480,000 pixels on screen
p. 6.8
11
Display Devices

• What is dot pitch?

• Measure of the distance between pixels
• Sometimes called pixel pitch
• Smaller the distance between the pixels, the
  sharper the image

Click to viewanimation
p. 6.9
12
Display Devices

• What is refresh rate?

• Speed at which monitor redraws images on the
  screen

p. 6.9
13
Display Devices

• What is a video card?

• Converts digital output from computer into analog
  video signal
• Controls how display device produces picture
• Also called graphics card or video adapter

p. 6.10
14
Display Devices

• How does video travel from the processor to a CRT
  monitor?

1 Processor sends digital data to video card
2 Video card converts digital data to analog
signal
3 Analog signal sent via cable to CRT monitor
4 CRT separates signal into red, green, and blue
signals
5 Electron guns fire color signals to front of
CRT
6 Image displays
p. 6.10 Fig. 6-10
15
Display Devices

• What is bit depth?

• Number of bits a video card uses to store
  information about each pixel
• Also called color depth
• Determines numberof colors a video card can
  display
• Greater the numberof bits, better the resulting
  image

p. 6.10
16
Display Devices

• What are video standards?

• Video Electronics Standards Association (VESA)
  develops video standards

p. 6.11 Fig. 6-11
17
Display Devices

• What are various video card configurations?

p. 6.11 Fig. 6-12
18
Printers

• What is a printer?

• Output device that produces text and graphics on
  paper
• Result is hard copy, or printout
• Two orientations

Click to view animation
p. 6.12 Fig. 6-14
19
Printers

• What is an impact printer?

• Forms characters by striking a mechanism against
  ink ribbon that physically contacts paper
• Ideal for printing multipart forms
• Can withstand dusty environments, vibrations, and
  extreme temperatures

p. 6.14
20
Printers

• What is a dot-matrix printer?

• Impact printer that produces printed images when
  tiny wire pins on print head mechanism strike
  inked ribbon
• Most use continuous-form paper

p. 6.14 Fig. 6-17
21
Printers

• How does a dot-matrix printer work?

• When ribbon presses against paper, it creates
  dots that form characters and graphics
• A higher number of pins (9 to 24) means printer
  prints more dots per character, which results in
  higher print quality

p. 6.14 Fig. 6-17
22
Printers

• What is a line printer?

• High-speed impact printer that prints entire line
  at a time
• Speed measured by number of lines per minute
  (lpm) it can print
• Band printer prints fully-formed characters using
  a hammer mechanism
• Shuttle-matrix printer is high-speed printer that
  works more like a dot-matrix printer

p. 6.14 Fig. 6-18
23
Printers

• What is a non-impact printer?

• Forms characters and graphics on piece of paper
  without actually striking paper

p. 6.15
24
Printers

• What is an ink-jet printer?

• Nonimpact printer forms characters and graphics
  by spraying tiny drops of liquid ink onto piece
  of paper
• Most popular type of color printer for home use

Click to view Web Link then click Ink-Jet
Printers
p. 6.15 Fig. 6-19
25
Printers

• What is the resolution of a printer?

• Sharpness and clarity of characters
• Measured by number of dots per inch (dpi)printer
  canoutput

p. 6.15 Fig. 6-20
26
Printers

• How does an ink-jet printer work?

p. 6.16 Fig. 6-21
27
Printers

• What is a laser printer?

• High-speed, high-quality nonimpact printer
• Prints text and graphics in very high-quality
  resolution, ranging from 600 to 1,200 dpi
• Typically costs more than ink-jet printer, but is
  much faster

Click to view Web Link then click Laser Printers
p. 6.16 Fig. 6-17
28
Printers

• How does a laser printer work?

1 Drum rotates as paper is fed through
2 Mirror deflects laser beam across surface of
drum
3 Laser beam creates charge that causes toner to
stick to drum
4 As drum rotates, toner transfers from drum to
paper
5 Rollers use heat and pressure to fuse toner to
paper
p. 6.17 Fig. 6-23
29
Printers

• What is a thermal printer?

• Generates images by pushing electrically heated
  pins against heat-sensitive paper
• Ideal for small devices, such as adding machines

p. 6.19 Fig. 6-24
30
Printers

• What is a plotter?

• Sophisticated printer used to produce
  high-quality drawings
• Large-format printer similar to plotter and is
  used to print quality color prints

p. 6.22
31
Memory Versus Storage

• What is access time?

• Amount of time it takes device to locate item on
  disk
• Defines speed of disk storagedevice

p. 7.4 Fig. 7-4
32
Memory Versus Storage

• What is capacity?

• Numberof bytes (characters) storage medium can
  hold

p. 7. 5 Fig. 7-3
33
Floppy Disks

• What are the parts of a floppy disk?

• Thin, circular, flexible film enclosed between
  two liners

Click to view Web Link then click Floppy Disks
p. 7.6 Fig. 7-5
34
Floppy Disks

• How does a floppy disk drive work?

p. 7. 7 Fig. 7-7
35
Floppy Disks

• What are tracks and sectors?

• Track is narrow recording band that forms full
  circle on disk surface
• Sector can store up to 512 bytes of data

80 tracks per side X 18 sectors per track X 2
sides per disk X 512 bytes per sector
1,474,560 bytes
p. 7.8 Fig. 7-8
36
Floppy Disks

• What is formatting?

• Process of preparing disk for reading and writing
• Formatting marks bad sectors as unusable

p. 7. 8 Fig. 7-9
37
Floppy Disks

• What is a write-protect notch?

• Small opening with a cover that you slide
• Protects floppy disks from being erased
  accidentally

p. 7. 9 Fig. 7-10
38
High-Capacity Disks

• What is a high-capacity disk drive?

• Uses disks with capacities of 100 MB and greater
• Primarily used to backup files and transfer files

Click to view Web Link then click Zip Drives
p. 7.9 Fig. 7-11
39
High-Capacity Disks

• What is a backup?

• Duplicate of file, program, or disk that you can
  use if original is lost, damaged, or destroyed

p. 7.9
40
Hard Disks

• What is a hard disk?

• High-capacity storage
• Consists of several inflexible, circular platters
  that store items electronically
• Components enclosed in airtight, sealed case for
  protection

p. 7. 10 Fig. 7-12
41
Hard Disks

• How does a hard disk work?

p. 7.11 Fig. 7-13
42
Hard Disks

• What is a cylinder?

• Location of a single track through all platters
• Single movement of read/write head arms can read
  same track on all platters

Click to viewanimation
p. 7. 11 Fig. 7-14
43
Hard Disks

• What is a head crash?

• Occurs when read/write head touches platter
  surface
• Spinning creates cushion of air that floats
  read/write head above platter

p. 7. 12 Fig. 7-15
44
Hard Disks

• What is a disk cache?

• Portion of memory processor uses to store
  frequently accessed items

p. 7. 12 Fig. 7-16
45
Hard Disks

• What is a partition?

• Formatted hard disk divided into separate areas
  called partitions
• Each partition functions as if it were a separate
  hard disk drive

p. 7. 12
46
Hard Disks

• What is a removable hard disk?

• Disk drive in which a plastic or metal case
  surrounds the hard disk so you can remove it from
  the drive
• Used for backup or to transfer files

p. 7. 13 Fig. 7-17
47
Hard Disks

• How does RAID work?

• Disk system that duplicates data, instructions,
  and information to improve data reliability

• Mirroring has one backup disk for each disk
• Striping stores data across multiple disks

p. 7. 14 Fig. 7-19
48
Compact Discs

• What is a compact disc (CD)?

CD-ROM

• Storage medium
• Most PCs include some type of compact discdrive
• Available invariety offormats

CD-RW
CD-R
DVDRW
DVD-ROM
p. 7. 17
49
Compact Discs

• How does a laser read data on a compact disc?

1 Laser diode shines light beam toward compact
disc
2 If light strikes pit, it scatters. If light
strikes land, it is reflected back toward laser
diode.
3 Reflected light deflected to light-sensing
diode, which sends digital signal of 1. Absence
of reflected light read as digital signal of 0.
p. 7. 18 Fig. 7-23
50
Compact Discs

• How is data stored on a compact disc?

• Typically stores items in single track
• Track divided into evenly sized sectors that
  store items

p. 7. 18 Fig. 7-24
51
CD-ROMs

• What is a CD-ROM?

• Compact disc that uses same laser technology as
  audio CDs for recording music
• Cannot erase or modify contents
• Typical CD-ROM holds about 650 MB
• Commonly used to distribute software and games

p. 7. 20
52
CD-ROMs

• What is the data transfer rate of a CD-ROM drive?

p. 7.20
53
CD-R and CD-RW

• What is a CD-R (compact disc-recordable)?

• Compact disc onto which you can record text,
  graphics, and audio
• Write on CD-R using CD burner (recorder) or CD-R
  drive and special software

• CD-R drive can read and write both audio CDs and
  standard CD-ROMs
• Cannot erase discs contents

p. 7. 22
54
CD-R and CD-RW

• What is a CD-RW (compact disc-rewritable)?

• Erasable disc you can write onmultiple times
• Must have a CD-RW disc,CD-RW software,and CD-RW
  drive

Click to view Web Linkthen click CD-RWs
p. 7. 22
55
CD-R and CD-RW

• How is an audioCD created?

Step 1 Artist composes song and creates CD
Step 2a Song stored on audio CD and purchased by
user OR Step 2b Song compressed and stored on
Internet
Step 3a User inserts audio CD into CD-ROM drive,
plays song, and copies it to hard disk OR Step
3b User downloads song as audio file to hard disk
Step 4 User copies file to CD-RW disc
Step 5 User listens to song on personal computer
or removes CD and listens to song on portable CD
player
p. 7. 23 Fig. 7-29
56
DVD-ROMs

• What is a DVD-ROM (digital video disc-ROM)?

• High capacity compact disc capable of storing
  from 4.7 GB to 17 GB
• Must have DVD-ROM drive or DVD player to read
  DVD-ROM
• Primarily used for movies
• Next-generation software will be delivered on DVD

Click to view video
p. 7.24 Fig. 7-30
57
DVD-ROMs

• How does a DVD-ROM store data?

• Two layers of pits are used, where lower layer is
  semitransparent
• Laser can read through it to upper layer
• DVDRW is a rewritable DVD

Click to view video
p. 7. 25 Fig. 7-31
58
Tapes

• What is tape?

• Magnetically coated ribbon of plastic capable of
  storing large amounts of data and information at
  a low cost
• Primarily used for backup

Click to view Web Link then click Tapes
p. 7. 26 Fig. 7-32
59
Tapes

• What is sequential access versus direct access?

p. 7. 26
60
The Keyboard

• What is a portable keyboard?

• Full-sized keyboard you conveniently can attach
  and remove from a handheld computer

p. 5.6 Fig. 5-7
61
The Keyboard

• What is an ergonomic keyboard?

• Designed to minimize strain on handsand wrists

• Ergonomics incorporates comfort, efficiency, and
  safety into design of items in workplace

p. 5.6 Fig. 5-8
62
The Keyboard

• What are alternative forms for commands?

• Many programs allow you to use button, menu, or
  function key to obtain same result

Command
Button
Menu
Function Key(s)
p. 5.4 Fig. 5-4
63
Mouse

• What is a mouse?

• Pointing device that fits under palm of hand
• Controls movement of pointer, also called mouse
  pointer, on screen
• Pointer on screen takes several shapes

Click to view video
p. 5.7
Click to view Web Link then click Mouse
64
Mouse

• How does a mechanical mouse work?

• Rubber or metal ball is on its underside
• Movement of mouse translates into signals
  computer understands

p. 5.7 Fig. 5-9
65
Mouse

• How does an optical mouse work?

• Senses light to detect mouses movement
• More precise than mechanical mouse
• Connect using a cable or wireless

p. 5.7 Fig. 5-10
66
Other Pointing Devices

• What is a trackball?

• Stationary pointing device with a ball on its top
• To move pointer, rotate ball with thumb, fingers,
  or palm of hand

Click to view Web Link then click Trackballs
p. 5.10 Fig. 5-13
67
Other Pointing Devices

• What is a touchpad?

• Small, flat, rectangular pointing device
  sensitive to pressure and motion

Click to view Web Link then click Touchpads
p. 5.10 Fig. 5-14
68
Other Pointing Devices

• What is a pointing stick?

• Pointing device shaped like pencil eraser
  positioned between keys on keyboard

Click to view Web Link then click Pointing
Sticks
p. 5.11 Fig. 5-15