Transcript 04Chapter Information Technology in Business

Chapter 4
Information Technology
in Business: Hardware
Management Information Systems, 3rd Edition
Effy Oz
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.
– Be able to classify computers into major
categories, and identify their strengths and
weaknesses.
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Learning Objectives
– 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
Information Systems
• What Is a Computer?
– A computer must handle four operations:
• Accept data
• Process data
• Store data and instructions
• Output data
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The Central Tool of Modern
Information Systems
Figure 4.1 All computers have the same basic components.
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The Central Tool of Modern
Information Systems
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
• Understanding Computer Processing:
– 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
– Two Components:
• Control unit
• Arithmetic logic unit (ALU)
– What is a Microprocessor?
• Carries signals that execute all processing
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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
• The 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
– Registers
• CPU chip has designated areas for temporary storage of information
and rapid retrieval.
– These storage areas are called registers.
– Internal Memory (used in actual processing of data inside
the computer)
• Random access memory (RAM)
• Read-only memory (ROM)
– External Memory (not involved in processing)
• Magnetic disks, magnetic tapes, optical discs
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A Peek Inside the Computer
• Memory
– Random Access Memory
• All instructions and data are stored before CPU fetches for processing
– Cache Memory
• Fast memory semiconductor chips (usually SRAM)
• Stores most frequently used instructions of programs the
computer runs
– Read-Only Memory
• Small part of internal memory
• Maintains instructions and data the user need and should
not change
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A Peek Inside the Computer
• Memory: Volatile vs. non-volatile
– Volatile (temporary)
• Depends on electrical current to maintain
information
– Such as RAM and registers
– Non-volatile (permanent)
• Programs and data stay in the chips when power is
off
– Accessible again when computer is turned back on
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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 (speed of processing, word size, the
maximum number of bits accessed by the CUP
from internal memory, and the capacity of
Buses used to facilitate internal
communications between CPU and internal
memory )
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Input Devices
• Keyboard
– QWERTY and Dvorak
– Ergonomic
• Mouse, Trackball, and Track Pad
• Touch Screen
• Source Data Input Devices
–
–
–
–
Source Data Technology
Banking
Credit Cards
Shipping
• 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
• Monitors
– 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
• Magnetic Tapes
• Magnetic Disks
• Optical Discs (Compact Discs)
– Recording Technology
– CD Drives
• Optical Tape
• Flash Memory
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External Storage Media
• Business Considerations of
Storage Media
– Trade-offs
– Modes of Access
• Sequential storage
• Direct storage
• Direct access storage devices
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External Storage Media
• Important Properties to Consider
– Capacity
– Speed
– Mode
– Cost
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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
• The Microcomputer Revolution
– Microcomputer: collective name for all
desktop computers
• Also known as personal computers (PCs)
• More powerful micros are sometimes called
workstations
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Classification of Computers
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Classification of Computers
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Classification of Computers
• Computers on the Go: Laptop, Hand-held,
and Tablet Computers
• Internet Appliances
• Reduced Instruction Set Computing
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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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Ethical and Societal Issues
Computers May Be Hazardous to Your Health
• Electromagnetic Radiation
– This small risk can be eliminated by using
Liquid Crystal Display monitor in lieu of
cathode ray terminal monitors
• Flat monitors not only emit negligible amounts of
electromagnetic radiation but are easier on the eyes
• Attempts to Legislate
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Ethical and Societal Issues
Computers May Be Hazardous to Your Health
• Casting Doubt
– Mayo Clinic 2001 study casts doubt that heavy
use of a PC is a main cause of carpal tunnel
syndrome
• Editorial comment to study says results might have
been influenced by sampled people and researchers
being employed by the same company.
– lack of a control group
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