--4InfoTech_Hardware.ppt 1226KB Mar 29 2010 04:55:11 AM

Information Technology
Hardware

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Learning Objectives


When you finish this chapter, you will:
 Recognize

major components of an electronic

computer.
 Understand how the different components
work.
 Know the functions of peripheral equipment.

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Learning Objectives

 Be

able to classify computers into major
categories, and identify their strengths and
weaknesses.
 Be able to identify and evaluate key criteria
when deciding what computers to purchase.
 Know the controversy regarding the health
hazards of computers.
 Recognize how to evaluate hardware so that
you can harness it to improve managerial
processes.
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The Central Tool of Modern IS


Four Basic Functions of Computers
 Accept

data
 Process data
 Store data and instructions
 Output data

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The Central Tool of Modern IS

Figure 4.1 All computers have the same basic components.

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The Central Tool of Modern IS

Figure 4.2 Organizations have moved from using large mainframes to using
networked PCs.

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Computers Communicating: Bits And Bytes


Computer recognizes two states: on or off
 Each



on or off signal represents a bit (binary digit)

Encoding Schemes
 Representation



of symbols by unique strings of bits

Counting Bases
 Decimal

system is “base 10”
 Binary system is “base 2”


Used by computers

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A Peek Inside the Computer

Figure 4.6 A look inside a computer

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A Peek Inside the Computer


The Central Processing Unit (CPU)
 The

brain of the computer
 Microprocessor


Carries signals that execute all processing

 Two

Components:

Control unit
 Arithmetic logic unit (ALU)


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A Peek Inside the Computer
 Microprocessor
Silicon

chip embedded with transistors,
or semiconductors

Figure 4.7 Schematic of how circuits on a chip would be open and
closed to represent the letter D in EBCDIC (11000100)

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A Peek Inside the Computer

Figure 4.8 What happens inside the CPU in one machine cycle executing the
operation 7 + 5

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A Peek Inside the Computer


Machine Cycle
 CPU’s

execution of four functions:

Fetch
 Decode
 Execute
 Store


 Functions

measured in small fractions of a

second
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A Peek Inside the Computer


Memory

 CPU

Registers
 Internal Memory
Random access memory (RAM)
 Read-only memory (ROM)


 External


Memory

Magnetic disks, magnetic tapes, optical discs

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A Peek Inside the Computer
 Computer

Power

Clock

rate (measured in cycles
per second)
Amount of information the CPU
can process per second
Speed determined only by
combination of both factors
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Input Devices
Keyboard
 Mouse, Trackball, and Track Pad
 Touch Screen
 Source Data Input Devices
 Imaging
 Speech Recognition


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Input Devices

Figure 4.10 Banks use magnetic-ink character recognition (MICR) to automate
their input procedures.

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Output Devices


Soft-Copy Output Devices
 Cathode-Ray

Tube (CRT) Monitor
 Flat-Panel Monitor
 Speech Output


Hardcopy Output Devices
 Nonimpact

Printers (most common)
 Impact Printers
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Output Devices

Figure 4.11 In an RGB monitor, the electron gun creates many different
colors and hues from three primary colors: red, green, and blue.

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External Storage Media
 Important

Properties to Consider

Capacity
Speed
Cost

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External Storage Media
Magnetic Tapes
 Magnetic Disks
 Optical Discs (Compact Discs)
 Optical Tapes


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External Storage Media
 Business

Considerations of
Storage Media
Trade-offs
Modes

of Access

 Sequential

Access
 Direct Access

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External Storage Media

Figure 4.12 Characteristics of storage media for business consideration

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Classification of Computers


Supercomputers
 The

largest, most powerful, and most expensive
 Used by universities, research institutions, and
large corporations


Mainframe Computers
 Less

powerful and less expensive than
supercomputers
 Used by businesses with large amounts of data
that need to be stored in a central computer

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Classification of Computers


Minicomputers
 Often

used as the host computer in a network
of smaller computers
 Priced in the tens of thousands to a few
hundred thousand dollars
 Manufacturers: DEC (VAX), IBM (AS/400),
and Hewlett-Packard

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Classification of Computers
 Compatibility
 Software

and peripheral devices from
one computer can be used with
another computer.
 In a networked environment,
computers need to communicate to
share databases and other computing
resources.
 In addition to power and cost,
compatibility is an extremely important
factor in purchasing decisions.
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Considerations in
Purchasing
Hardware
 What should you consider when buying

hardware?
 Power -- speed, size of memory, storage
capacity
 Expansion and upgrade capability
 Ports for external devices like printers,
hard disks, communication devices
 Ergonomics: Keyboard, Monitor
 Vendor reliability, warranty policy, vendor
support
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Considerations in the Purchase of Hardware
Factor

What to Look For

•Power

Greater frequency and word size, larger

•Expandability

Greater number of board slots for additional RAM

•Ports

Greater number of ports for printer, external hard
disk, communication devices and other peripherals

•Ergonomics

Greater comfort and safety

•Compatibility

Comparability with many other computers and
peripheral devices, as swell as software packages

•Footprint

Smaller area

•Support

Availability of telephone and on-line support for
troubleshooting

•Warranty

Longer warranty period

•Cost

Lower cost

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Ethical and Societal Issues
Computers May Be Hazardous to Your Health


Physical and Emotional Stress
 General

physical and emotional stress
 Muscular-skeletal problems


Repetitive Stress Injuries (RSI)

 Vision

problems

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