Orasa T.
13
Computer Hardware
13
Learning Objectives
• Identify the major types and uses of
microcomputer, midrange, and
mainframe computer systems.
• Outline the major technologies and
uses of computer peripherals for
input, output, and storage.
13 Learning Objectives (continued)
• Identify the components and
functions of a computer system.
• Identify the computer system and
peripherals you would acquire or
recommend for a business of your
choice.
13
Section I
• Computer Systems: End User and
Enterprise Computing
13
Types of Computer Systems
• All computers are systems of input,
processing, output, storage, and
control components.
• Three basic categories
– Mainframe
– Midrange computers
– Microcomputers
13
Types of Computer Systems (continued)
• Mainframe
– Enterprise systems
– Superservers
– Transaction processors
– Supercomputers
13
Types of Computer Systems (continued)
• Midrange
– Network servers
– Minicomputers
– Web servers
– Multi-user systems
13
Types of Computer Systems (continued)
• Microcomputers
– Personal computers
– Network computers
– Technical workstations
– PDAs
– Information appliances
13
Microcomputer Systems
• The most important category of
computers
– Desktop
– Laptop
• Workstation computers
• Network servers
13
Microcomputer Systems (continued)
• Selection criteria
– Solid performance at a reasonable price
– Operating system ready
– Connectivity
13
Microcomputer Systems (continued)
• Network computers
– Designed primarily for use with the
Internet and corporate intranets
– For specialized or limited computing
applications
– Lower cost of purchase, upgrades,
maintenance, and support
13
Microcomputer Systems (continued)
• Network computers (continued)
– Other benefits
•
•
•
•
Ease of software distribution and licensing
Computing platform standardization
Reduced end user requirements
Improved manageability
13
Microcomputer Systems (continued)
• Information appliances
– PDAs
– Set-top boxes and video-game
consoles
– Wireless PDAs
– Cellular and PCS phones
13
Microcomputer Systems (continued)
• Computer terminals
– Dumb terminals
– Intelligent terminals
– Network terminals
– Transaction terminals
13
Midrange Computer Systems
• Multi-user systems that can manage
networks of PCs and terminals
• Less costly to buy, operate, and
maintain than mainframes
• Popular as network servers
• Minicomputers
13 Mainframe Computer Systems
• Large, fast, powerful
• Handle high transaction processing volumes or
complex computational problems
• Super servers for large client/server networks
and high-volume Internet websites
• Popular for data mining and warehousing
13
Mainframe Computer Systems (continued)
• Supercomputers
– Extremely powerful systems
specifically designed for scientific,
engineering, and business
applications requiring extremely high
speeds for massive numeric
computations
– Use parallel processing architectures
– Process at speeds measured in
gigaflops and teraflops
13 The Computer System Concept
• Computers are organized according
to the following system functions:
– Input
•
•
•
•
•
•
Keyboards
Touch screens
Pens
Electronic mice
Optical scanners
Convert data into electronic form
13
The Computer System Concept (continued)
– Processing
• Central Processing Unit (CPU)
– Two subunits
» Arithmetic-Logic Unit (ALU)
» Control Unit
13
The Computer System Concept (continued)
– Output
• Video display units
• Printers
• Audio response units
• Convert electronic information into humanintelligible form
13
The Computer System Concept (continued)
– Storage
•
•
•
•
Store data and software instructions
May also include cache memory
Primary storage unit (hard drive)
Secondary storage
– Magnetic disks
– Optical disk drives
13
The Computer System Concept (continued)
– Control
• The registers and other circuits of the
control unit interpret software instructions
and transmit directions to the other
components of the computer system
13
The Computer System Concept (continued)
• Computer processing speeds
– Milliseconds (thousandths of a second)
– Microseconds (millionths of a second)
– Nanoseconds (billionths of a second)
– Picoseconds (trillionths of a second)
13
The Computer System Concept (continued)
– Clock speeds
• Megahertz (MHz)
– Millions of cycles per second
• Gigahertz (GHz)
– Billions of cycles per second
13
Section II
• Computer Peripherals: Input, Output,
and Storage Technologies
13
Peripherals
• Generic name given to all input,
output, and secondary storage
devices
• Depend on direct connections or
telecommunications links to the CPU
• All peripherals are online devices
13
Input Technologies
• Natural user interface
– Enter data and commands directly into
a computer
• Electronic mice and touch pads
• Optical scanning, handwriting recognition,
voice recognition
13
Pointing Devices
• Used for entering data and text
• Work with your operating system’s
graphical user interface (GUI)
– Electronic mouse
– Trackball
– Pointing stick
– Touch pad
– Touch screen
13
Pen-Based Computing
• Used in many hand-held computers
and PDAs
– Digitizer pen
– Graphics tablet
13 Speech Recognition Systems
• Digitize, analyze, and classify your
speech and its sound patterns
• Allow operators to perform data
entry without using their hands to
key in data or instructions
• Speaker-independent
• Voice-messaging computers
13
Optical Scanning
• Read text or graphics and convert
them into digital input
• Employ photoelectric devices to
scan the characters being read
13 Optical Scanning (continued)
• Optical character recognition (OCR)
– Reads OCR characters & codes
• Merchandise tags
• Product labels
• Sort mail, score tests
• Hand-held optical scanning wands
– Reads bar coding
– Universal Product Code (UPC)
13
Other Input Technologies
• Magnetic stripe technology
– Credit cards
• Smart cards
– Embedded microprocessor chip
• Debit, credit, and other cards
• Digital cameras
– Still cameras
– Digital camcorders
13
Other Input Technologies (continued)
• Magnetic ink character recognition
(MICR) technology
– Used by banks to sort and post checks
and deposit slips
– 14 characters of a standardized design
– Reader-sorters
• Video
• Print
• Storage
13
Video Output
• Video monitors
– Cathode ray tube (CRT)
– Liquid crystal displays (LCDs)
13
Printed Output
• Inkjet
– Spray ink onto the page one line at a
time
• Laser
– Use an electrostatic process similar to
a copier
13
Storage Trade-Offs
13 Storage Trade-Offs (continued)
• Computer storage fundamentals
– Information is stored through the
presence or absence of electronic or
magnetic signals
• Binary representation
– 1 = ON
– 0 = OFF
13 Storage Trade-Offs (continued)
• Computer storage fundamentals
(continued)
– Bit
• The smallest element of data
• May have a value of either one or zero
– Byte
• Basic grouping of bits
• Typically, a byte consists of 8 bits and
represents one character of data
13 Storage Trade-Offs (continued)
• Computer storage fundamentals
(continued)
– Storage capacities
• Kilobytes (KB)
– 1,000 bytes
• Megabytes (MB)
– 1 million bytes
13 Storage Trade-Offs (continued)
• Computer storage fundamentals
(continued)
• Gigabytes (GB)
– 1 billion bytes
• Terabytes (TB)
– 1 trillion bytes
• Petabyte (PB)
– 1 quadrillion bytes
13 Storage Trade-Offs (continued)
• Direct and sequential access
– Terms direct access and random
access describe the same concept
– An element of data or instructions can
be directly stored and retrieved by
selecting and using any of the locations
on the storage media
• Each storage position
– Has a unique address
– Can be individually accessed in approximately
the same time
13 Storage Trade-Offs (continued)
• Direct and sequential access
(continued)
– Sequential access
• Does not have unique storage addresses
• Serial process
• Data are recorded one after another in a
predetermined sequence.
• Locating an individual item requires
searching all of the data until the desired
item is located
13 Storage Trade-Offs (continued)
13
Semiconductor Memory
• Primary storage of your computer
• Advantages
– Small size
– Great speed
– Shock and temperature resistant
• Disadvantage
– Volatility
13
Semiconductor Memory (continued)
• Two basic types of semiconductor
memory
– RAM – random access memory
• Volatile memory
• Read/write memory
• “working” memory
13
Semiconductor Memory (continued)
– ROM – read only memory
• Nonvolatile
• Used for permanent storage
• Can be read but not erased or overwritten
– Variations of ROM
• PROM
– Programmable read only memory
• EPROM
– Erasable programmable read only memory
13
Magnetic Disk Storage
• Most common form of secondary
storage
• Data is recorded on tracks in the
form of tiny magnetized spots
• Thousands of bytes recorded on
each track
13
Magnetic Disk Storage (continued)
• Types of Magnetic Disks
– Floppy disks
– Zip disks
– Hard disk drives
13
Magnetic Disk Storage (continued)
• Redundant arrays of
independent disks (RAID)
– Provides large capacities with high
access speeds
– Data are accessed in parallel over
multiple paths from many disks
– Fault tolerant
– Storage area networks (SANs)
• Fiber channel LANs that connect many
RAID units
13
Magnetic Tape Storage
• Used as secondary storage
• Also used in robotic automated drive
assemblies
• Lower-cost storage
• Archival storage
13
Optical Disk Storage
• CD-ROM
• CD-R
• CD-RW
• DVD
• DVD-ROM
• DVD-RAM
13 Optical Disk Storage (continued)
• Business applications
– Image processing
– Provide access to reference materials
in a convenient, compact form
– videos
13
Discussion Questions
• Do you agree with the statement:
“The network is the computer”?
• What trends are occurring in the
development and use of the major
types of computer systems?
13 Discussion Questions (continued)
• Do you think that network computers
(NCs) will replace personal
computers (PCs) in business
applications?
• Are networks of PCs and servers
making mainframe computers
obsolete?
13 Discussion Questions (continued)
• What trends are occurring in the
development and use of peripheral
devices? Why are those trends
occurring?
• When would you recommend the use of
each of the following:
– Network computers
– NetPCs
– Network terminals
– Information appliances in business applications
13 Discussion Questions (continued)
• What processor, memory, magnetic
disk storage, and video display
capabilities would you require for a
personal computer that you would
use for business purposes?
• What other peripheral devices and
capabilities would you want to have
for your business PC?
13
Real World Case 1 – City of Richmond
& Tim Beaty Builders
• The Business Value of PDAs
• What are the business benefits of
PDAs for business applications?
• What are the limitations of PDAs for
business use?
13
References
• James A. O'Brien; George M. Marakas.
Management Information Systems:
Managing Information Technology in the
Business Enterprise 6th Ed., Boston:
McGraw-Hill/ Irwin,2004