Transcript Chapter 1 Introduction to Computers

Lecture 1
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ITBIS 105
Chapter 1
Introduction to
Computers
What Is a Computer?
How is a computer defined?
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Electronic device operating under the control of
instructions stored in its own memory
Processes data into
information
Accepts data
Produces and stores results
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Input and Output
Input
 Data entered to a computer system for processing.
 from people or machines to computers
Output
 the presentation of results of processing.
 from computer to humans or other machines
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Data and Information
Data
Information
Raw facts or unprocessed
items such as text,
numbers, images, audio
and video
Data that is organized,
meaningful, and useful
Input
(Data)
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Process
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Output
(Information)
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Hardware and Software
Hardware
Physical parts of the computer that you can
touch, feel and weigh
Software
Non physical parts of the computer – the
instructions or programs that tell the
hardware how to behave
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The Components of a Computer
The electric, electronic and mechanical components of
the computer - hardware
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Input devices
Output devices
System unit
Storage devices
Communication
devices
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The Components of a Computer
What is an _____
input device?
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Hardware used
to enter data
and instructions
Into a computer
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The Components of a Computer
What is an ______
output device?
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Hardware that
conveys
information
to a user
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Computer Outputs
Softcopy output
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output on monitor or sounds from the
speakers which are temporary
Hardcopy output
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the output from printers, or printed output that
can be physically handled, folded
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The Components of a Computer
What is the system unit?
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Box-like case
containing
electronic
components
used to process
data
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The Components of a Computer
What is storage?
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Holds data, instructions, and information
for future use
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The Components of a Computer
What is communication device?
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Hardware component that enables a computer to send
and receive data, instructions and information to and
from one or more computers.
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A widely used communication device is the modem,
which is used to connect your computer to the Internet
through telephone line.
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Computer Software
What is software?
set of programs / instructions that tells the computer
what to do and how to do it
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System software
 Application software
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Computer Software
What is system software?
Programs that control or maintain the operations of
the computer and its devices
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Operating System (OS)
• set of programs that coordinates all the activities of a computer.
• provides the interface between the user and the computer’s hardware.
• Examples are Microsoft DOS, Microsoft Windows 95, 98, 2000, XP,
UNIX, LINUX…
Utility Programs allow the users to
perform functions such as printing file,
copying file, listing file names etc…
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Computer Software
What is application software?
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Programs that perform
specific tasks for users
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Software Suite
Popular software applications
bundled together as a single unit
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Word
Processing
Spreadsheet
Database
Presentation
Graphics
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Why Is a Computer So Powerful?
The computer’s strengths
Speed
Accuracy
Reliability
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Storage
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Consistency
Communications
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Lecture 2
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Categories of Computers
What are the categories of computers?
Personal computers
Mobile computers
Midrange servers
Mainframe computers
Supercomputers
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Personal Computers
Most popular personal computers are either desktop or notebook PCs
What is a desktop computer?
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Designed so all of the components fit on or under
a desk or table
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Mobile Computers
What is a notebook computer?
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Also called a laptop
Portable, small enough to fit on
your lap
Generally more expensive than
a desktop computer
Can operate on batteries or a
power supply or both
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Mobile Computers
What is a tablet PC?
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Resembles a letter-sized slate
Allows you to write on the
screen using a stylus
Smaller version is the
modular computer
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Handheld Computers
What is a handheld computer?
Small
enough to fit
in your
hand
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Used
by mobile
employees such as
meter readers and
delivery people
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Handheld Computers
What is a personal digital assistant (PDA)?
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Provides personal organizer functions
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Calendar
Appointment book
Address book
Calculator
Notepad
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Handheld Computers
What are Smart phones?
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Web-enabled telephone
Allow you to check e-mail
and access the Internet
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Categories of Computers
Midrange server
 greater processing power,
storage capacity and reliability
than personal computers
 Typically supports several
hundred and sometimes up to a
few thousand connected
computers.
 Known as minicomputers in
the past
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Categories of Computers
Mainframe
 Large, expensive, very powerful,
computer that can handle hundreds
or thousands of connected computers
simultaneously
 Large storage capacity
 Used in large organizations
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Categories of Computers
Supercomputer
 The fastest, most powerful,
most expensive computer.
 Used for applications
requiring complex
mathematical calculations
such as medicine, aerospace,
automotive design, online
banking, weather forecasting,
nuclear energy research &
petroleum exploration
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Computer Applications in Society
What are some examples
of computer applications
in society?
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Education
Finance
Government
Healthcare
Science
Publishing
Travel
Industry
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Networks
What is a network?
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Collection of computers and devices connected
via communications devices and transmission
media
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Each computer or device connected to a the
network is called a node.
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Networks
What are the advantages of using a network?
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Facilitate communication
Share hardware
Share software
Share data and
information
Transfer funds
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Types of Networks
Local Area Network (LAN)
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Network in limited
geographical area such
as home or office
building
Metropolitan Area Network
(MAN)
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connects LANs in city or
town
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Types of Networks
Wide area network (WAN)
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Network that covers
large geographic
area using many
types of media
Internet is world’s
largest WAN
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Network Topology
Layout of computers and devices in network
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Popular topologies are bus, ring, and star
Bus network
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All computers and devices
connect to central cable,
or bus
Inexpensive and easy to
install
Easy to add or delete
devices from network
Failure of one device does
not affect the rest of the
network
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Network Topology
Ring network
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Cable forms closed ring, or loop,
with all computers and devices
arranged along ring
Data travels from device to device
around entire ring, in one
direction
If a computer or device on a ring
network fails, all devices before
the failed device are unaffected,
but those after the failed device
cannot function.
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Network Topology
Star network
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All devices connect to a
central system
All data transferred from one
computer to another passes
through the central system
Needs only one control unit
But if control unit fails, the
whole network fails
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