Computer Hardware

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7 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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Computer Hardware

13

Orasa T.


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


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

Learning Objectives (continued)


Computer Systems: End User and
Enterprise Computing

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Section I


All computers are systems of input,
processing, output, storage, and
control components.



Three basic categories


Mainframe


Midrange computers


Microcomputers

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Types of Computer Systems


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

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Types of Computer Systems (continued)


The most important category of
computers


Desktop


Laptop



Workstation computers



Network servers

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Microcomputer Systems


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


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Microcomputer Systems (continued)


Network computers (continued)


Other benefits


Ease of software distribution and licensing


Computing platform standardization


Reduced end user requirements


Improved manageability


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Microcomputer Systems (continued)


Information appliances


PDAs



Set
-
top boxes and video
-
game
consoles



Wireless PDAs



Cellular and PCS phones

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Microcomputer Systems (continued)


Computer terminals


Dumb terminals



Intelligent terminals



Network terminals



Transaction terminals


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Microcomputer Systems (continued)


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

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Midrange 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

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Mainframe Computer Systems


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


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Mainframe Computer Systems (continued)


Computers are organized according
to the following system functions:


Input


Keyboards


Touch screens


Pens


Electronic mice


Optical scanners


Convert data into electronic form


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The Computer System Concept


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 human
-
intelligible 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


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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

The Computer System Concept (continued)


Computer Peripherals: Input, Output,
and Storage Technologies


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Section II


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


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Peripherals


Natural user interface


Enter data and commands directly into
a computer


Electronic mice and touch pads


Optical scanning, handwriting recognition,
voice recognition


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Input Technologies


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

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Pointing Devices


Used in many hand
-
held computers
and PDAs


Digitizer pen


Graphics tablet


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Pen
-
Based Computing


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


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Speech Recognition Systems


Read text or graphics and convert
them into digital input


Employ photoelectric devices to
scan the characters being read


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Optical Scanning


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)


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Optical Scanning (continued)


Magnetic stripe technology


Credit cards



Smart cards


Embedded microprocessor chip


Debit, credit, and other cards



Digital cameras


Still cameras


Digital camcorders


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Other Input Technologies


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


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Other Input Technologies (continued)


Video monitors


Cathode ray tube (CRT)


Liquid crystal displays (LCDs)


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Video Output


Inkjet


Spray ink onto the page one line at a
time



Laser


Use an electrostatic process similar to
a copier


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Printed Output

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Storage Trade
-
Offs


Computer storage fundamentals


Information is stored through the
presence or absence of electronic or
magnetic signals


Binary representation


1 = ON


0 = OFF


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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

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Storage Trade
-
Offs (continued)


Computer storage fundamentals
(continued)


Storage capacities


Kilobytes (KB)


1,000 bytes


Megabytes (MB)


1 million bytes


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Storage Trade
-
Offs (continued)


Computer storage fundamentals
(continued)


Gigabytes (GB)


1 billion bytes


Terabytes (TB)


1 trillion bytes


Petabyte (PB)


1 quadrillion bytes


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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


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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


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Storage Trade
-
Offs (continued)

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Storage Trade
-
Offs (continued)


Primary storage of your computer


Advantages


Small size


Great speed


Shock and temperature resistant


Disadvantage


Volatility

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Semiconductor Memory


Two basic types of semiconductor
memory



RAM


random access memory


Volatile memory


Read/write memory


“working” memory


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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

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Semiconductor Memory (continued)


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


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Magnetic Disk Storage


Types of Magnetic Disks


Floppy disks



Zip disks



Hard disk drives


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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


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Magnetic Disk Storage (continued)


Used as secondary storage


Also used in robotic automated drive
assemblies


Lower
-
cost storage


Archival storage


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Magnetic Tape Storage


CD
-
ROM


CD
-
R


CD
-
RW



DVD


DVD
-
ROM


DVD
-
RAM


13

Optical Disk Storage


Business applications


Image processing


Provide access to reference materials
in a convenient, compact form


videos


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Optical Disk Storage (continued)


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?

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Discussion Questions


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?

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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

Discussion Questions (continued)


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

Real World Case 1


City of Richmond

& Tim Beaty Builders

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


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