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Chapter 05 Data
Storage Technology
1. A storage device consists of a read/write mechanism and
a storage medium.
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2. Wait states increase CPU and computer system
performance.
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3. Primary storage extends the limited capacity of CPU registers.
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4. The CPU moves data and instructions continually between
registers and primary storage.
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5. With current technology, secondary storage speed is
typically faster than primary storage speed.
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6. Block size is normally stated in bytes and is generally
the same between storage devices, especially in a single storage device.
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7. 512- and 4096-byte blocks are the most common data
transfer units for magnetic disks.
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8. Volatility is a matter of degree and conditions.
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9. Magnetic tape and disk are considered volatile storage media.
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10. The physical structure of a storage device’s read/write
mechanism and storage medium determines the ways in which data can be
accessed.
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11. Serial access time depends on the current position of
the read/write mechanism and the position of the target data item in the
storage medium.
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12. Cost per unit decreases as an access method moves from
serial to random to parallel.
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13. Secondary storage is generally expensive compared with
primary storage.
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14. Capacitors can charge and discharge much faster than
batteries.
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15. SRAM has higher density then DRAM.
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16. Electrical current can generate a magnetic field but a
magnetic field cannot generate electricity.
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17. Disk drives share one set of read/write circuits among
all read/write heads.
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18. HTH switching time is the most important component of
access time.
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19. Because sequential access time is so much faster than
average access time, disk performance is improved dramatically if related
data is stored in sequential sectors.
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20. Communication channel capacity is generally a
restriction on a single disk drive’s data transfer rate.
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21. Coercible material per sector is greater at the center
than in the platter edge.
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22. To increase capacity per platter, disk manufacturers
divide tracks into two or more zones and vary the sectors per track in each
zone.
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23. Computing average access time is more complex when
sectors are more densely packed on the platter’s outer portions because the
assumption that an average access requires moving the read/write head over
half the tracks is no longer valid.
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24. SSDs are much more tolerant to shock and other negative
environmental factors commonly encountered with portable devices, such as
multifunction cell phones, netbooks, and laptop computers.
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25. Magnetic disk drives have an advantage over SSDs in
power consumption.
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26. Most optical storage media can retain data for decades
because they aren’t subject to magnetic decay and leakage.
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27. Rewritable DVDs use a single standard adopted by the
entire industry.
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28. Magnetic and optical storage are currently direct competitors.
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29. The write operation for recordable discs is
destructive, so recordable disc formats can be written only one time.
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30. Magneto-optical technology peaked in the mid-1980s.
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31. The ____ is the device or substance that actually
holds data.
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32. ____ is the most important characteristic
differentiating primary and secondary storage.
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33. A ____ is a CPU cycle spent waiting for access to an
instruction or data.
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34. ____ in the CPU are storage locations for instructions
and data.
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35. Storage device speed is called ____.
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36. Access times for secondary storage devices are
typically expressed in ____ or microseconds.
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37. ____ is a generic term for describing secondary storage
data transfer units.
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38. A storage device or medium is ____ if it holds data
without loss over long periods.
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39. A storage device or medium is ____ if it can’t hold
data reliably for long periods.
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40. A ____ storage device stores and retrieves data items
in a linear, or sequential, order.
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41. A ____ device isn’t restricted to any specific order
when accessing data.
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42. Data is represented in the CPU as ____.
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43. The term ____ describes primary storage devices that
are implemented as microchips, can read and write with equal speed, and can
randomly access bytes, words, or larger data units.
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44. Modern computers use memory implemented with ____.
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45. ____ is implemented entirely with transistors.
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46. ____ stores each bit by using a single transistor and
capacitor.
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47. Programs usually access instructions and data items
____.
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48. ____ is a read-ahead RAM that uses the same clock
pulse as the system bus.
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49. Memory devices comprised of semiconductors and other
forms of RAM with long-term or permanent data retention are generically known
as ____.
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50. Software stored in NVM is called ____.
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51. The ____, a newer packaging standard, is essentially a
SIMM with independent electrical contacts on both sides of the module.
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52. The tendency of magnetically charged particles to lose
their charge over time is called ____.
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53. The surface area allocated to store on a bit is called
the ____.
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54. A(n) ____ is a ribbon of plastic with a coercible
(usually metallic oxide) coating.
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55. A ____ consists of all tracks at an equivalent distance
from the edge or spindle on all platter surfaces.
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56. A single disk sector usually holds ____ or 4096
bytes.
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57. Multiple hard drives can be enclosed in a single
storage cabinet; this arrangement is referred to as a ____.
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58. Read/write circuitry uses ____ data to compensate for
minor variations in rotation speed and other factors that might disturb the
precise timing needed for reliable reading and writing.
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59. The time needed to move from one track to another is
called ____, typically measured in milliseconds.
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60. The time the disk controller must wait for the right
sector to rotate beneath the heads is called ____.
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61. ____ is the sum of average access delay and the time
required to read a single sector.
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62. ____ is the time required to read the second of two
adjacent sectors on the same track and platter.
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63. A disk with many program and data files scattered on it
is said to be ____.
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64. A ____ reorganizes disk content so that a file’s
contents are stored in sequential sectors, tracks, and platters.
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65. A ____ is a storage device that mimics the behavior of
a magnetic disk drive but uses flash RAM or other NVM devices as the storage
medium and read/write mechanism.
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66. Current SSDs use ____ as the storage medium.
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67. Modern SSDs use a technique called “____” to spread
write operations around the storage medium, thus evening out the impact of
destructive writes and extending the storage device’s useful life.
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68. Sony and Philips originally developed compact disc (CD)
technology for storing and distributing music in the ____ format.
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69. In a CD, flat areas in the reflective layer that
represent bit values are called “____.”
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70. In a CD, concave dents in the reflective layer that are
used to represent bit values are called “____.”
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71. A storage device consists of a read/write mechanism
and a(n) ____________________.
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72. A(n) ____________________ provides the interface between
the storage device and system bus.
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73. A CPU with a 1 GHz clock rate needs a new instruction
and supporting data every ____________________.
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74. ____________________ is the time required to perform
one complete read or write operation.
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75. The term ____________________ describes the data
transfer unit for magnetic disk and optical disc drives.
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76. ____________________ is the only widely used form of
serial access storage.
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77. A(n) ____________________ device can access multiple
storage locations simultaneously.
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78. Primary storage devices must closely match CPU speed
and word size to avoid ____________________.
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79. Each refresh operation in DRAM is called a(n)
____________________.
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80. ____________________ is a read-ahead RAM that uses the
same clock pulse as the system bus.
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81. ____________________ stores bit values by using two
magnetic elements, one with fixed polarity and the other with polarity that
changes when a bit is written.
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82. ____________________ RAM is the most common
non-volatile RAM used today.
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83. ____________________ is the capability of a substance
or magnetic storage medium to accept and hold a magnetic charge.
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84. The stored charge held within a bit of magnetic storage
must be above the ____________________ for a read operation to be successful.
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85. For a two-dimensional storage medium like a disk
platter, having the length and width of the area that stores one bit
increases storage capacity by a factor of ____________________
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86. Magnetic disk media are flat, circular
____________________ with metallic coatings that are rotated beneath
read/write heads.
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87. A(n) ____________________ is one concentric circle of
a platter, or the surface area that passes under a read/write head when its
position is fixed.
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88. In a magnetic disk drive, a(n) ____________________ is
mounted on the end of an access arm for each platter surface.
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89. Average access time is computed under the assumption
that two consecutive accesses are sent to ____________________ locations.
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90. Over time, file contents tend to become
____________________ in many nonsequential sectors.
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91. A disk drive’s data ____________________ rate is a
summary performance number combining the physical aspects of data access with
the electronic aspects of data transfer to the disk controller or system.
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92. The ____________________ data transfer rate is the
fastest rate the drive can support.
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93. Optical storage devices store bit values as variations
in ____________________.
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94. Current optical storage devices use a(n)
____________________ storage medium.
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95. In a magneto-optical drive, the laser polarity shift
used in reading is known as the “____________________ effect.”
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96. List important characteristics among which storage
devices and technologies vary.
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97. How is a storage device’s data transfer rate computed?
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98. Explain the two ways that storage device portability is
typically implemented.
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99. What is an advantage of optical storage over magnetic
storage?
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100. Describe phase-change optical discs.
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