The University of Akron
Summit College
Business Technology Department
Computer Information Systems
2440: 145 Operating Systems
Introduction to Computers
Instructor: Enoch E. Damson
Computer

A machine that performs four basic
operations known as the information
processing cycle (input, processing,
output, and storage)




Input – computer gathers data from users
Process – data is converted into information
Storage – data or information is stored for
future use
Output – data or information is retrieved from
the computer
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Types of Computers

The four basic types of computers
are:




Supercomputers
Mainframes
Minicomputers
Microcomputers
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Types of Computers…


Supercomputers – fastest, most expensive, large and
powerful computers for specialized tasks such as
mathematical calculations, weather tracking, satellite
monitoring, etc
Mainframes – large computers designed to handle
huge processing jobs in large corporations and
government agencies

Mainframe computers multitask – perform different types of
tasks at the same time

Minicomputers – handle the computer needs of

Microcomputers – designed to meet individual needs
smaller corporations

Some of the most common types of microcomputers are:
desktops, laptop/notebook, personal digital assistants
(PDAs)
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Types of Microcomputers
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5
Computer Information System (IS)


A collection of components that work
together to process data into
information
Components include:






Hardware
Software
Procedures
Data
People
Network
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Computer Information System…
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Hardware



The physical components of the computer
controlled by the software
The way these components are put together and
arranged is called system hardware
configuration
Types of hardware devices (peripherals)
include:




Input Devices
Systems Unit
 Processor Unit
 Internal memory
Storage Devices
Output Devices
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Types of Hardware Devices
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Input Devices


Used to enter data into the
computer for processing
Examples include:





Keyboard
Mouse
Scanner
Digital camera
Video camera
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Keyboard


The primary input device for computers
Uses the following types of keys to send
data to the computer






Alphanumeric keys
Control keys
Function keys
Cursor control keys
Toggle and other keys
Multimedia and Internet control keys
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Keyboard Keys

Alphanumeric keys – sends alphabets
and numeric values to the computer



Numeric keypad – provides alternate method
of quickly entering numbers
Control keys – the Ctrl, Alt, and
Windows keys that are used in
combination with other keys to provide
shortcuts or increased keyboard
functionality
Function keys – numbered F1 through
F12 and generally associated with certain
software-specific commands
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Keyboard Keys…



Cursor control keys – arrow keys that
allow users to move the insertion point
Toggle and other keys – the Insert,
Num Lock, Caps Lock and other keys used
for various purposes like navigation and
editing
Multimedia and Internet control keys
– available on most modern keyboards for
functions such as muting or volume
control, opening a Web browser, sending
an email, etc
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Keyboard Keys
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System Unit

Holds the processing hardware, electrical
power supply, disk drives, circuit cards,
ports for connecting other hardware and
the motherboard (system board)


Motherboard – ties everything in the system
unit together
The motherboard holds two very important
parts of the computer:
 Processor (central processing unit (CPU)
or microprocessor)
 Memory (RAM)
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Motherboard
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The Processor


The brain of the computer that controls all the commands
and tasks of the computer
Has three basic main parts:




Measured by the speed at which they are capable of
processing data – also known as clock speed


Control Unit – obtains instructions from the computer’s
memory and interprets these instructions and executes them
Arithmetic-Logic Unit (ALU) – performs all the arithmetic
(math operations) and logical (comparisons) operations for
the computer
Registers – a small set of temporary storage cells used to
store data and instructions needed frequently
Processing speed is measured in megahertz (MHz) – in
millions – and gigahertz (GHz) – in billions
Examples include:


Pentium, Celeron, Centrino (by Intel Corporation)
Athlon, Sempron, Turion (by Advanced Micro Devices)
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Memory


Holds:



Data – raw facts for processing
Instructions – rules for processing data
Information – processed data

Random Access Memory (RAM) – the volatile part of memory that stores
information temporarily
Read-Only Memory (ROM) – the nonvolatile part of memory on which
instructions have been prerecorded to help start the computer and perform
other tasks
Two basic types of memory include:


Memory is measured by its size in bytes, kilobytes (thousands),
megabytes (millions), and gigabytes (billions)



Bit (Binary Digit) – the smallest unit of information in computers that is made
up of 0s and 1s
Byte – represents a single character and consists of 8 bits
ASCII (American Standard Code for Information Interchange) – one of the
coding schemes used to represent characters in 8-bit bytes


Can represent a maximum of 256 characters (incl. uppercase and lowercase letters,
numbers, punctuation marks, and special symbols)
Word – a group of bytes


System-dependent
Vary from 16 bits (2 bytes), 32 bits ( 4 bytes) or even 64 bits (8 bytes)
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Storage Devices
 Used to store data and information permanently
 Data is generally stored using one of the following
forms:
 Magnetic storage – uses sectors that divide tracks to
store data
 E.g. hard disks, tapes, floppy disks, zip disks
 Optical storage – also uses tracks and sectors but data is
saved using a laser beam
 E.g. Compact discs (CDs), digital video discs (DVDs)
 Flash memory – uses solid-state technology which is
completely electronic and has no moving mechanical
parts
 E.g. Flash drives (memory sticks), cards used in digital
cameras, MP3 players, etc

Storage devices are measured in bytes, kilobytes,
megabytes, gigabytes
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Examples of Storage Devices
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Output Devices
 The devices used to display and print data and
information
 E.g. monitor, printer, speakers, etc
 Monitors output soft copy and their resolution
identifies the number pixels (picture elements) per
square inch that appear on a screen
 Most monitors today can display at least 256 colors
 The two main categories of monitors are:
 Cathode ray tubes (CRT) – can be curved or flat and relatively
inexpensive
 Flat-panel/LCD monitors – use liquid crystal display (LCD)
technology and are much slimmer and expensive
 Printers output hard copy and their resolution is
measured in dots per inch (dpi)
 The two main categories of printers are:
 Impact printers – like dot matrix printers that use small keys to
strike an ink ribbon against a paper
 Non-impact printers – like ink-jet printers and laser printers
that do not touch the paper when printing
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Examples of Output Devices

Monitors

Printers
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Software


Software (program) - a set of
instructions that direct the
computer to accomplish certain
tasks
The two major categories of
software are:


System software
Application software
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System Software


Provides the instructions needed for the computer
to run
The ”background software” that manages the
fundamental operations of a computer system
including:



Starting up (booting) the computer
Executing programs
There are 4 types of system software:




Operating systems – E.g. Windows, Mac OS,
Linux
Utilities programs – Norton Antivirus
Device drivers – printer software
Programming languages – Java, C++
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Operating System


Controls basic input and output, allocates
system resources, manages storage
space, maintains security, and detects
equipment failure
Examples include:




DOS
Windows
UNIX
Mac OS, etc
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Application Software


”End-user” software that performs useful
tasks such as word processing, desktop
publishing, etc
Kinds of application software include:





Word processing software – e.g. Microsoft
Word
Spreadsheet software – e.g. Microsoft Excel
Database software – e.g. Microsoft Access
Presentation software – e.g. Microsoft
PowerPoint
Communication & Organization software –
e.g. Microsoft Outlook
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Procedures


Rules or guidelines for people to
follow when using software,
hardware, and data
E.g. Software Manuals
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People


Making people more productive is
what computers are all about
Examples include:




Analysts
Designers
Developers
Users
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Data


Raw facts entered into the
computer system for processing
Processed to produce information
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Networks

Two or more computers connected in some way to
share hardware, software programs, data and other
resources


Node – each object (computer, printer, etc) connected
to a network
The two main types of networks are:


Local area network (LAN) – uses direct cables,
radio, or other signals to link computers within a
small geographic area like a building or group of
buildings
Wide area network (WAN) – uses longdistance transmission media to link computers
separated by a few miles or even thousands of
miles
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Network Configurations

The two main categories of network
configurations are:


Peer-to-peer (P2P) networks –
most commonly found in homes and
small-businesses with each node
capable of communicating with every
other node
Client/server networks - consist of a
server (host computer) and clients
(workstations)
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Networks Topology (Topography)


The different types of network architecture – how
computers and other devices are arranged and
connected
The most common topographic layouts include:



Bus network – no server but each node connects to a
central high-speed line (bus)
Ring network – all nodes connect to a circular line
around which data travels in only one direction
Star network – each node connects to a centrally
located switch to communicate with other nodes



The most frequently used networking style for businesses
Has a server to which all clients and other devices are
connected
Wireless network – devices connect to other computers
and network resources using radio signals, microwaves,
satellite signals, and other wireless media
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Network Topologies
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Network Cables

Computers can be connected to a network using
devices like:

Coaxial cables – typically used by most cable TV systems


The ends are usually made with RF (radio frequency)
connectors
Twister pair cables (shielded and unshielded) – two
conductors are twisted together for the purposes of
canceling out electromagnetic interference (EMI) from
external sources


The ends are usually made with RJ (registered jack) 45 to plug
into computer network interfaces
Two main types include:



Fiber-optic cables – a glass or plastic fiber that carries
light along its length


Shielded Twisted Pair (STP) cables –
Unshielded Twisted pair (UTP) /Ethernet cables – primarily used for telephones
and commonly for computer networking
Used by most high-speed Internet cable connections
Wireless – transfers information without using wires
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Coaxial Cable
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Twisted Pair Cable
Shielded Twisted Pair (STP)
Unshielded Twisted Pair (UTP)
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Fiber-Optic Cable
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Ports


Where all the peripheral devices
connect to the computer to enable
data exchange
Because input and output devices
can exchange data with the
computer using different methods,
they might require different ports
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Types of Ports

Serial and parallel ports are two of the
oldest types of ports found on a
computer

Serial ports – can only send data one bit at a
time



Transfer data 115 Kilobits per second (Kbps) at
most
Devices that use serial ports include the mouse,
modem
Parallel ports – send data in groups of bits, at
transfer rates of up to 500 Kbps

Printers often use parallel ports
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Faster Types of Ports

Universal serial bus (USB) ports – able to interface
with several different peripheral devices



USB 2.0 can attain a rate of 480 Mbps or 480,000 Kbps
FireWire ports - usually used to connect digital
cameras or digital video recorders to a computer
Connectivity ports – used to connect to a local
network or to the Internet

Examples include:


Modem ports – resemble phone jacks and are used to
connect the modem to a phone system and enable dial-up
Internet access
Ethernet port - a bit larger than the standard phone jack
and used for network access and can also be used to
connect a cable modem or router
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Types of Ports
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