Transcript continued

Introduction to Information Technology
2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
Chapter 3:
Computer Hardware
Prepared by:
Roberta M. Roth, Ph.D.
University of Northern Iowa
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-1
Chapter Preview
 In this chapter, we will study:
The hardware components of an information
system:
• CPU (central processing unit)
• Memory (primary and secondary storage)
• Input devices
• Output devices.
The classification of computers by power.
Strategic issues regarding hardware.
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-2
The Central Processing Unit (CPU)
The CPU
Input
Devices
Control
ALU
Unit
Registers
Primary
Storage
Output
Devices
Communication
Devices
Secondary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-3
The CPU (continued)
 A microprocessor that executes instructions
to perform processing tasks. Component
parts are:
Control Unit
Arithmetic-Logic Unit
Registers
Primary Storage
The CPU
Control
ALU
Unit
Registers
Primary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-4
The CPU (continued)
 Control Unit
Access program instructions
Decode (interpret)
instructions
Control flow of data
throughout system
Data flows through paths
called buses
The CPU
Control
ALU
Unit
Registers
Primary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-5
The CPU (continued)
 Arithmetic-Logic Unit
Perform computations on data
Perform comparisons on data
The CPU
Control
ALU
Unit
Registers
Primary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-6
The CPU (continued)
 Registers
High speed storage areas
Hold data and instructions
The CPU
Control
ALU
Unit
Registers
Primary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-7
The CPU (continued)
 Primary Storage (Main Memory)
Stores instructions from programs
Stores data to be processed
The CPU
Control
ALU
Unit
Registers
Primary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-8
The CPU (continued)
 Machine Instruction Cycle
An instruction is fetched from primary storage
by the Control Unit
The Control Unit decodes the instruction
The ALU receives the data and the instruction
and performs the calculation or comparison
The result is stored in primary storage.
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-9
The CPU (continued)
 Computer performance is measured in part by
the number of Machine Instruction Cycles
performed per second.
 Factors affecting this performance include:
 Clock Speed
 Word Length
 Bus Width
 Line Width
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-10
The CPU (continued)
 Microprocessors evolved rapidly due to
Miniaturization of transistors
Decreasing distance between transistors on the
chip (decreasing line width)
Improved conductivity (flow) of electricity
Improved instruction sets programmed into
the chip.
 Smaller, faster, cheaper, more powerful
chips with each generation.
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-11
Computer Memory
The CPU
Input
Devices
Control
ALU
Unit
Registers
Primary
Storage
Output
Devices
Communication
Devices
Secondary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-12
Computer Memory Basics
 Computers are digital, and represent data in bit
patterns
 Bit is shorthand for Binary digIT. The binary
system consists of two values: 0 & 1
 8 bits = byte
 Bytes are the basic measure of storage in
computers
 ASCII Code assigns a unique character to each
pattern of 0s &1s in a byte.
 Kilobytes, Megabytes, Gigabytes, Terabytes
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
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Primary Storage (Main Memory)
 Main memory is a temporary storage area
that holds three things…
information you are working with
the application software you are using
the operating system software
 Increasing memory capacity increases the
performance of the system
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-14
Primary Storage (Main Memory)
 Types of Primary Storage
 Registers – part of the CPU; very fast; very limited capacity
 Random Access Memory (RAM) – memory chips on
motherboard; general storage of program instructions and data;
volatile
 Cache Memory – faster than RAM; used to provide
intermediate storage between secondary storage and RAM
 Read-only Memory (ROM) – chips storing permanent
instructions needed by computer; non-volatile
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-15
Secondary Storage
 Non-volatile storage of data and
instructions
 Huge storage capacity
 Cheaper than Primary Storage
 Slower than Primary Storage
 Magnetic and optical storage media
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-16
Secondary Storage Types
 Magnetic tape
 Cheap, slow, sequential access: good for backup
 Magnetic Disk
 Floppy
 Hard disk
 Zip drive
 Memory Cards and Cartridges
 Optical
 CD-ROM, CD-RW
 DVD
 FMD-ROM
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
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Storage for the Enterprise
 Enterprise Storage Systems – provide
coordinated, secure, managed storage for all
enterprise data.
Redundant array of independent disks (RAID)
Storage area network
Network-attached storage
 Storage Service Providers – third party
storage utilities
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-18
Computer Classifications
 Computers are commonly classified by their
processing power:
 Supercomputers
 Mainframes
 Midrange
 Workstations
 Microcomputers
 Computing appliances
 Classification boundaries are blurred.
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-19
Computer Classifications
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-20
Input Technology
The CPU
Input
Devices
Control
ALU
Unit
Registers
Primary
Storage
Output
Devices
Communication
Devices
Secondary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-21
Input Technologies
 Human-oriented
 Keyboard
 Mice / trackball
 Touch screens
 Stylus
 Joystick
 Microphone
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
 Automated
 ATMs
 POSs
 Optical Scanners
• OMR
• MICR
• OCR
 Voice recognition
 Sensors
 Cameras
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Output Technology
The CPU
Input
Devices
Control
ALU
Unit
Registers
Primary
Storage
Output
Devices
Communication
Devices
Secondary
Storage
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-23
Output Technologies
 Monitors
 Printers
 Voice
 Multimedia
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-24
Strategic Hardware Issues
 Productivity
 Will employees’ personal productivity increase as microprocessor
power and speed increases?
 Changing Work Styles
 Will new work styles will benefit employees and the firm as a
whole?
 New Products and Services
 Is the organization ready and able to take advantage of the
new products and services that hardware advances may make
possible for the business?
 Improved Communication
 Is the organization ready to use multimedia for knowledge
sharing?
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-25
Chapter Summary
 Basic role and function of the CPU
 Primary and secondary storage
 Classifications of computers based on processing
power
 Variety and purpose of input devices
 Variety and purpose of output devices
 Consideration of strategic issues raised by the
advances in hardware technology
Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-26
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Introduction to Information Technology, 2nd Edition
Turban, Rainer & Potter
© 2003 John Wiley & Sons, Inc.
3-27