Transcript Unit C: Computer Software

Computer Concepts-Illustrated
Introductory, Sixth Edition,
Enhanced
Unit B
Computer Hardware
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Unit Objectives
Introduce storage technology
Compare storage technologies
Compare storage media and devices
Explore hard disk technology
Explore CD/DVD technology
Explore solid state storage
Computer Concepts, 6th Edition, Enhanced
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Unit Objectives
Examine input devices
Compare display devices
Compare printers
Understand expansion slots,
cards, and ports
Explore peripheral devices
Computer Concepts, 6th Edition, Enhanced
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Overview
Computers use various
technologies to store and retrieve
data and programs
Storage: magnetic, optical, and
solid state
Input and output devices
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Introducing storage technology
Storage technology: enables
computers to store and retrieve
data and programs
 Storage medium: disk, hard drive,
tape, memory card, CD or DVD that
holds the data
 Storage device: drive or reader that
records and retrieves data
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Introducing storage technology
Data is copied from a storage device
to RAM
 RAM (random access memory) is a temporary,
volatile storage place
 RAM is the connection between storage device
and storage media
 Recording data: “writing data” or “saving a file”
 Retrieving data: “loading data” or “opening a
file”
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The science of data representation
Data representation is the
conversion of letters, sounds,
and images to electronic signals
Binary system: 1s and 0s, or “on”
and “off”
Storage media use different
methods for transforming 1s and
0s into permanent signals
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Comparing storage technologies
Magnetic storage:
 Magnetizes microscopic particles on disk
or tape surface
 Fairly permanent, but modifiable and not
very durable
 Hard disks, floppies, Zip disks, and tape
 Read-write head orients particles
positively or negatively to represent 1s
and 0s
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Comparing storage technologies
Magnetic storage
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Comparing storage technologies
Optical storage:
 Stores microscopic light spots (lands) and dark
spots (pits) on a disc surface
 Low-power laser reads data
 CDs, DVDs
Solid State Storage
 Non-volatile, erasable, low-power chip
 A card reader transfers data to computer
 Fast access because no moving parts
 Very durable, high cost
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Exploring floppy disk technology
Standard floppy disks are 3 1/2”,
with 1.44MB capacity
Same technology used for Zip
disks
Inexpensive, removable, but not
efficient because of small storage
size
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Comparing storage media and devices
Versatility
 Floppy drives can only access floppies
 DVD drives can access DVDs, DVD
movies, audio & data CDs, and CD-Rs
Durability
 Susceptibility to environment
 Optical and solid state are more durable
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Comparing storage media and devices
Speed
Access time (milliseconds)
• Average time to locate & read data
Random: ability to jump to data
(CD/DVD)
• Sequential: must read from beginning
Data transfer rate (seconds)
• Amount of data a device can move from
storage medium to computer
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Comparing storage media and devices
Capacity
 Amount of data stored (MB, KB, GB, TB)
 Disk density: closeness of data on surface
Drive bays
 Storage device “parking spaces” on
system unit case
 5 ¼” or 3 ½”
 Internal bays used for hard disk drives
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Exploring hard disk technology
High storage capacity, fast access
 Not as durable
Hard disk/hard drive/fixed disk
 1 or more platters and their read-write heads
 Speed is measured in rpm (revolutions per
minute)
 Ads specify: capacity, access time, speed
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Exploring hard disk technology
Platter
 Flat, rigid disk made of aluminum or glass,
coated with magnetic iron oxide particles
 Platters divided into tracks and sectors
• Cylinder: Vertical stack of tracks
Controller
 Circuit board that positions the disk and readwrite heads to locate data
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Exploring hard disk technology
DMA (direct memory access)
 Allows computer to directly transfer data from
drive to RAM
 Frees up processor for other tasks
Head crash
 Jarring or interference of read-write head
 Causes damage to data
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Understanding tape storage
Tape drive (device) and tape
(medium)
Internal (drive bay) or external
(by cable)
Sequential, slow access
Tape cartridges are most popular
media for tape drives
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Exploring CD/DVD technology
CDs & DVDs use optical storage
 Lasers read pits & lands to interpret data
Three types:
 ROM: Read-only, cannot be changed
 R: recordable, can make permanent
changes
 RW: rewritable, data can be recorded
and modified using phase change
technology
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Exploring CD/DVD technology
CD and DVD drive
capabilities
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What is Blu-ray?
DVD format developed for HD
video and large amounts of data
 Recording, rewriting, and playback
 2 hours of HD, 13 hours of standard TV
 Uses short “blue” laser wavelength
 Standard DVDs use longer “red” lasers
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Exploring Solid State Storage
Portable, fast access, low power
Used for mobile devices and
transporting data between devices
Non-volatile, erasable chips
 Circuitry arranged in a grid with gates that
open (1) and close (0)
 Stores data without using external power
 Some devices need a card reader
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Exploring Solid State Storage
USB flash drive
 Plugs directly into USB
port
 “Pen drives” or “keychain
drives”
 Open, edit, delete and
run files as if they were
stored on your hard disk
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Exploring Solid State Storage
CompactFlash (CF)
cards
 Matchbook-sized, high
storage, fast access
 Use a card reader, good
for high-end digital
cameras
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Exploring Solid State Storage
MultiMedia cards (MMC)
 Built-in controller, inexpensive
SecureDigital cards (SD)
 Based on MMC, but faster data transfer
 Cryptographic security protection for
copyrighted material
SmartMedia cards
 “Solid state floppy disks”
 Least durable
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Why use solid state storage?
High-capacity, durable, fast
Digital camera cards
 Can hold hundreds of pictures
 Card can be connected to computer to
transfer files
 Card can be erased and reused
Good for transferring data
between devices or computers
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Examining input devices
Keyboard and pointing device are
primary input devices
Other input devices include
scanners, cameras, and tablets
Keyboards
 Keypads: typing, numeric, navigation
 Function keys [F1] can perform tasks
 Modifier keys [Ctrl] can be used for shortcuts
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Examining input devices
Pointing devices manipulate onscreen pointer and controls
 Mouse: has buttons to click
• Mechanical: uses ball to track position
• Optical: uses light beam to track position
 Notebooks use pointing sticks, trackpads
or touchpads, and trackballs
 Joysticks used for computer games
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Comparing display devices
Graphics cards
 Contain video memory that stores screen
images as they are processed
 Amount of memory relates to speed
 Can be built into motherboard, or can be a
small circuit board
Plasma screens
 Illuminates colored fluorescent lights
 Compact, lightweight, expensive
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Comparing display devices
CRT (cathode ray tube) monitors
 Used to be only option for desktops
 Beams electrons to screen to activate dots of
color to create an image
 Refresh rate: speed screen is repainted
LCD (liquid crystal display) monitors
 Used on notebook computers
 Clear display, low radiation emission, portable
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Comparing display devices
Image quality is measured by:
 Resolution: maximum pixels on the screen
 Screen size: inches between diagonal corners
of screen
• Viewable image size is actual viewing area
• Viewing angle width is how far to the side you can
still see the screen image
 Dot pitch (s): distance between pixels
 Color depth: number of colors a monitor and
graphics card can display
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Comparing printers
Quality and price are affected by:
 Resolution: density of grid of dots that create an image
• Measured in dpi (dots per inch)
 Speed: pages per minute
 Duty cycle: pages per month
Printers connected by ports
Computer sends data and instructions to
printer
 Printer Control Language is most popular
 Publishers use PostScript
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Comparing printers
Printer types:
 Ink jet: small, inexpensive, good quality
 Photo: slower, professional quality
 Laser: high volume, good quality
 Dot matrix: slower, can be used for
carbons
 Sold ink or thermal wax: used in
businesses
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Understanding expansion slots, cards,
and ports
Data travels between computer
components over circuits
 Called a data bus
 Expansion bus: between RAM and peripherals
Expansion slots
 4-8 sockets on motherboard to plug in
expansion cards, such as graphics, sound,
modem, network
 Desktops have to three types: ISA, PCI, AGP
 Notebooks have PCMCIA
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Understanding expansion slots, cards,
and ports
Expansion port: connector that
passes data in and out of computer
or peripheral device
 Also called jacks or connectors
 USB ports are most popular
• On front of system unit
• Mice, scanners, printers, joysticks, storage
• Most are recognized when they are plugged in
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Exploring peripheral devices
Enhance computer’s functionality
 Projection devices show display on a
large screen
 Scanners input pages of text or images
into digital format
 Multifunction devices are both input and
output
 Digital cameras, graphics tablets, Web
cams
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Exploring peripheral devices
Must be connected to motherboard
 Often by cable to a port
 Expansion cards: used when the right kind of
port isn’t available
 To install device, unplug computer and ground
yourself for safety
Plug and play automatically installs
Device drivers
 Software to communicate between device and
computer
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Unit Summary
Storage: store and retrieve data
Input devices: keyboard, mouse
Output devices: monitor or printer
Devices connect through
expansion slots, cards, ports
Peripheral devices enhance
capability
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Computer Hardware
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