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INFORMATION
TECHNOLOGY
(MIS 3301)
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INFORMATION
TECHNOLOGY
1.0 Computers: Tools form Information
Age
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The nature of Computers
• There fundamental characteristics:
– Speed
– Reliability
– Storage Capability
• Followed by products:
– Productivity
– Decision making
– Cost reduction
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Computer uses
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Education
Graphics
Retailing
Energy
Law enforcement
Transportation
Money
Agriculture
Paperwork
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Government
Home
Health and Medicine
Robotics
The human connection
The science
Connectivity
Training
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Basic Components of Computer
Secondary storage
Secondary storage device
stores data and programs
Input device sends data to the
central processing unit
Input
Central processing unit (CPU)
executes computers instructions
Memory holds data and
programs currently in use
Output device makes processed
data (information) available
Output
Processing
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Personal Computer Hardware
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Input: What Goes In
• Input is the data that you put into the computer system for
processing.
– Typing on a keyboard. The keys on a computer keyboard are arranged
in much the same way as those on a typewriter. The computer responds
to what you enter; that is, it "echoes" what you type by displaying it on
the screen in front of you.
– Pointing with a mouse. A mouse is a device that is moved by hand over
a flat surface. As the ball on its underside rotates, the mouse movement
causes corresponding movement of a pointer on the computer screen.
Pressing buttons on the mouse lets you select commands.
– Scanning with a wand reader or bar-code reader. These devices,
which you have seen used by clerks in retail stores, use laser beams to
read special letters, numbers, or symbols such as the zebra-striped bar
codes found on many products.
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Output: What Comes Out
• The result produced by the central processing unit.
• Output is usable information--that is, raw input data that has been
processed by the computer into information. Common forms of
output are text, numbers, graphics, and even sounds.
• The most common output devices are computer screens and
printers.
– A screen, the visible part of the monitor, can vary in its form of display,
producing text, numbers, symbols, art, photographs, and even video, in
full color.
– Printers produce printed reports as instructed by a computer program.
Many printers, particularly those associated with personal computers,
can print in color.
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Secondary Storage
• Secondary storage provides additional storage separate
from memory. Recall that memory holds data and
programs only temporarily; thus there is a need for
secondary storage.
• Two most common secondary storage media are:
– A magnetic disk can be a diskette or a hard disk.
– Magnetic tape is used primarily with large computer systems.
This tape usually comes on a cartridge and is similar to tape that
is played on a tape recorder.
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The Complete Hardware System
• The hardware devices attached to the computer are called peripheral
equipment.
• Peripheral equipment includes all input, output, and secondary
storage devices. In most personal computers, the CPU and disk
drives are all contained in the same housing, a metal case; the
keyboard, mouse, and screen are separate.
• In larger computer systems, however, the input, processing, output,
and storage functions may be in separate rooms, separate buildings,
or even separate countries.
• The information produced by the central processing unit may then be
transmitted to the international offices, where it is printed out. Meanwhile, disks with stored data may be kept at the bank headquarters,
and duplicate data may be kept on disk or tape in a warehouse
across town for safekeeping
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Networking
• Many organizations find that their needs are best served by a
network, a computer system that uses communications equipment
to connect computers and their resources.
• Resources include printers and hard disks and even software and
data. In one type of network, a local area network (LAN), personal
computers in an office are connected together so that users can
communicate with one another.
• Users can operate their personal computers independently or in
cooperation with other computers to exchange data and share
resources. The networking process can be much more complex; we
will describe how large computers can be involved in networks in the
chapter on networking.
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The Internet
• The Internet, sometimes called simply "the
Net," is the largest and most far-flung
network system of them all, connecting
users worldwide.
• The Internet is not really a single network
but a loosely organized collection of
thousands of networks.
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The Internet
• The Internet.
– At his or her own computer, a user
accesses the server computer
– Probably over the phone line.
– The server computer communicates with
the Internet, perhaps passing on e-mail
messages or requests for certain web
sites, and picking up responses.
– Incoming messages, e-mail, or requested
Internet information are returned to the
original requesting computer. This backand-forth communication goes on as long
as the user wishes to remain connected
to the Internet.
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The Internet: Getting Connected
• To access the Internet, a user's computer must connect
to a type of computer called a server.
• Each server uses the same special software called
TCP/IP (for Transmission Control Protocol/Internet
Protocol); it is this standard that allows different types of
computers to communicate with each other.
• The supplier of the server computer, often called an
Internet service provider (ISP), charges a fee, usually
monthly, based on the amount of service provided.
• Once a user has chosen a service provider, he or she will
be furnished with the information needed to connect to
the server and, from there, to the Internet.
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The Internet: Getting Around
• The most attractive method used to move around the
Internet is called browsing.
• Using a program called a browser, you can use a mouse
to point and click on screen text or pictures to explore the
Internet, particularly the World Wide Web (WWW or the
Web), an Internet subset of text, images, and sounds
linked together to allow users to peruse related topics.
• Each different location on the Web is called a web site
or, more commonly, just a site. You may have heard the
term home page; this is just the first page of a web site.
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Classification of Computers
• Computers come in sizes from tiny to monstrous,
in both appearance and power. The size of a
computer that a person or an organization needs
depends on the computing requirements.
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Supercomputers
Mainframes
Personal Computers
Notebook Computers
Handheld Computers (PDA and Pocket PC)
Midrange Computers (minicomputers)
Mainframes
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