Chapter 4
Information Technology
in Business:
Hardware
The Central Tool of Modern
Information Systems
Four Basic Functions of
Computers
 Accept data
 Process data
 Store data and instructions
 Output data
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All computers have the same basic components.
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The Central Tool of Modern
Information Systems
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)
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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
 Two
signals that execute all processing
Components:
 Control
unit
 Arithmetic logic unit (ALU)
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Microprocessor
Microprocessor
 Silicon
chip embedded with transistors,
or semiconductors
letter D : 11000100
Schematic of how circuits on a chip would be open and closed to represent the
letter D in EBCDIC (11000100)
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–CPU’s execution of four
functions:
1.Fetch
2. Decode
3.Execute 4. Store
What happens inside the CPU in one machine cycle executing the operation 7 + 5
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Machine Cycle
Machine Cycle

CPU’s execution of four functions:
Fetch
 Decode
 Execute
 Store


Functions measured in small fractions of a second
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TYPES OF MEMORY
Memory

Internal Memory
Random access memory (RAM)
 Read-only memory (ROM)


External Memory

Magnetic disks, magnetic tapes, optical discs
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Computer Power
Computer Power

Clock rate (measured in cycles per second)

Amount of information the CPU can
process per second
1Mhz= 1 million Machine Cycle

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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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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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
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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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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 Purchasing
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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SEQUENTIAL & PARALLEL PROCESSING
SEQUENTIAL
PARALLEL
Program
Program
TASK 1
CPU
RESULT
Program
CPU
CPU
CPU
TASK 1
TASK 2
TASK 3
RESULT
TASK 2
CPU
RESULT
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CLIENT / SERVER
CLIENT
REQUESTS
SERVER
DATA,
SERVICE
USER INTERFACE
DATA
APPLICATION
APPLICATION FUNCTION
FUNCTION
NETWORK RESOURCES
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