Chapter 7 Storage

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Chapter 7Storage
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Memory Versus Storage

• What is storage?

• The media on which data, instructions, and
  information are kept, as well as the devices that
  record and retrieve these items

p. 7. 2 Fig. 7-1
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Memory Versus Storage

• What is memory?

• A temporary holding place for data and
  instructions
• Consists of one or more chips on the motherboard
• Sometimes called primary storage

p. 7. 3
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Memory Versus Storage

• How does storage differ from memory?

• Storage also called secondary storage, auxiliary
  storage, permanent storage, or mass storage
• Storage holds items such as data, instructions,
  and information for future use
• Storage is nonvolatile

p. 7. 4
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Memory Versus Storage

• What is reading and writing?

p. 7. 4
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Memory Versus Storage

• What is access time?

• The amount of time it takes the device to locate
  an item on a disk
• Defines the speed of a disk storage device

Memory (RAM)
Hard Disk
Compact Disc
Floppy Disk
Tape
p. 7.4 Fig. 7-4
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Memory Versus Storage

• What is capacity?

Storage Term
Number of bytes
Abbreviation

• The number of bytes (characters) a storage medium
  can hold
• Manufacturers use many terms to define the
  capacity of storage media

Kilobyte
KB
1 thousand
Megabyte
MB
1 million
1 billion
Gigabyte
GB
Terabyte
1 trillion
TB
Petabyte
PB
1 quadrillion
p. 7. 4 Fig. 7-3
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Access Types

• What is sequential access vs. direct access?

p. 7. 26
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Tapes

• What is tape?

• A magnetically coated ribbon of plastic capable
  of storing large amounts of data and information
  at a low cost
• Slow access
• Sequential access ONLY
• Often used for backup/historical data

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

• What is a floppy disk?

• A portable, inexpensive storage medium
• Consists of a thin, circular, flexible plastic
  disk with a magnetic coating
• Enclosed in a square-shaped plastic shell
• Todays standard disk is 3.5 wide, 1.44MB

p. 7. 7
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Floppy Disks

• What is formatting?

• The process of preparing a disk for reading and
  writing
• Formatting marks bad sectors as unusable

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

• How do you care for a floppy?

• A floppy disk can last at least seven years
• Proper care helps to maximize a disks life

p. 7.9
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Floppy Disks

• What is a write-protect notch?

• A small opening with a cover that you slide up or
  down
• Protects floppy disks from accidentally being
  erased

write-protected
not write-protected
p. 7. 9 Fig. 7-10
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High-Capacity Disks

• What is a high-capacity disk drive?

• A disk drive that uses disks with capacities of
  100 MB and greater

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

• What is a backup?

• A duplicate of a file, program, or disk that you
  can use if the original is lost damaged, or
  destroyed
• High-capacity disks are often used to back up
  important data and information

p. 7.9
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Hard Disks

• Consists of several inflexible, circular platters
  that store items electronically
• Also called a hard disk drive or a fixed disk

• What a hard disk?

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

• What is a disk cache?

• A portion of memory that the processor uses to
  store frequently accessed items

• A cache controller manages cache and thus
  determines which items cache should store

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

• What is a removable hard disk?

• A disk drive in which a plastic or metal case
  surrounds the hard disk so you can remove it from
  the drive
• A popular, reasonably priced, removable hard disk
  is the Jaz disk by Iomega

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

• What is RAID?

• Redundant array of independent disks
• A type of hard disk system that connects several
  smaller disks into a single unit that acts like a
  single large hard disk
• More reliable than a traditional disk system but
  quite expensive

p. 7.14 Fig. 7-18
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Hard Disks

• What utilities maintain a hard disk drive?

• Windows provides many maintenance and monitoring
  utilities for a hard disk on the System Tools
  submenu

Click to view Web Link then click Utilities
p. 7. 15 Fig. 7-20
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Hard Disks

• What is an Internet hard drive?

• A service on the Web that provides storage to
  computer users
• Sometimes called online storage
• Many offer storage free of charge
• Revenues come from advertisers

p. 7. 16 Fig. 7-21
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Hard Disks

• What are advantages of an Internet hard drive?

p. 7. 16
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Compact Discs

• What is a compact disc (CD)?

CD-ROM

• A flat, round, portable, metal storage medium.
  CD 650MB DVD4.7-17GB
• Also called an optical disc
• Available in a variety of formats

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

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

• Items are stored using microscopic pits
  (indentations) and land (flat areas) that are in
  the middle layer of the disk
• A laser light reads items from the compact disc

Step 1 A laser diode shines a light beam toward
the compact disc
Step 2 If light strikes a pit, it scatters. If
light strikes land, it is reflected back toward
the laser diode.
Step 3 Reflected light is deflected to a
light-sensing diode which sends digital signals
of 1 to the computer. Absence of reflected light
is read as a digital signal of 0.
p. 7. 18 Fig. 7-23
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PC Cards

• What is a PC Card?

• A thin, credit card-sized device
• Fits into a PC Card slot on a notebook other
  personal computer
• Different types and sizes add storage, additional
  memory, communications, and sound capabilities to
  a computer

Click to view Web Link then click PC Cards
p. 7. 28 Fig. 7-35
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Miniature Mobile Storage Media

• What is miniature mobile storage media?

• Handheld devices use miniature mobile storage
  media to augment internal storage

Clik! Disk
Cartridge Digital cameras, notebook computers
40 MB
Memory Card Digital cameras, handheld computers,
notebook computers, printers, cellular telephones
CompactFlash
2 to 256 MB
Microdrive
1 GB
Memory card Digital cameras, handheld computers,
music players, video cameras
SmartMedia
2 to 128 MB
Memory Card Digital cameras, handheld computers,
photo printers, cellular telephones
p. 7. 28 Fig. 7-37
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Miniature Mobile Storage Media

• What is a smart card?

• Stores data on a thin microprocessor embedded in
  the card
• Similar in size to a credit card
• Read smart card with a specialized card reader
• Information on the smart card can be read and
  updated

p. 7. 29 Fig. 7-39
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Miniature Mobile Storage Media

• What are the types of smart cards?

• Intelligent smart card contains a processor and
  has input, process, output, and storage
  capabilities
• Memory card has only storage capabilities

p. 7. 29
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Miniature Mobile Storage Media

• What is electronic money?

• A means of paying for goods and services over the
  Internet
• Also called digital cash

p. 7. 29
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Microfilm and Microfiche

• What are microfilm and microfiche?

• Store microscopic images of documents on roll or
  sheet film
• Images recorded onto film using a computer output
  microfilm (COM) recorder
• Images can only be read with a microfilm or
  microfiche reader

p. 7. 30 Fig. 7-40
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Summary

• What are suggested storage devices for computer
  users?

Large Business
Home
Power
p. 7. 31 Fig. 7-42