Essential Computer Concepts

FIRST COURSE
Essential
Computer
Concepts

XPObjectives
• Compare the types of computers
• Describe the components of a computer system
• Describe input and output peripheral devices
• Examine data representation and the ASCII and
UNICODE codes
• Define memory and storage
• Examine image representation
• Identify the hardware and software that are used
for data communications and to establish a network
connection

XPObjectives
• Explain how Internet access, e-mail, and the
World Wide Web affect the use of computers
• Describe potential security threats to computers
and protection methods
• Discuss the types of system software and their
functions
• Identify popular application software
• Describe how data is shared among different
types of application software

XP
New Perspectives on Microsoft Office 2007: Windows XP Edition 4
What Is a Computer?
• A computer is an electronic device that accepts
data and instructions from a user, manipulates
the data according to the instructions, displays
the information in some way, and stores the
information for retrieval later

XPWhat is a computer?
• An electronic device that accepts input,
processes the data and instructions, produces
output from the processing that is useful and
meaningful and stores the results for future
use.

XP
How Does A Computer Know What To Do?
• It must be given a detailed set of instructions
that tell it exactly what to do.
• These instructions are called a computer
program, or software.

XP
Types of Computers
• Personal computers (PCs)
– Desktop computers
– Notebook (laptop) computers
– Tablet PCs
• Handheld computers
– PDA (personal digital assistant)
– MP3 players
– Cell phones
• Mainframe computers
• Supercomputers

XP
Types of Computers
Personal Computers
PDA
Super Computers
Desktop
Notebook
Tablet PC

XP
Computer Systems
• Includes computer hardware and software
–Hardware refers to the physical components
of a computer
–Software refers to the intangible components
of a computer system, particularly the
programs the computer needs to perform a
specific task

XP
System Software
• System software
manages the
fundamental operations
of your computer
– Operating system
• System resource
• Multitasking
– Utilities
– Programming Languages

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Application Software
• Application software enables you to perform
specific computer tasks, such as document
production, spreadsheet calculations, and
database management
– Document production software

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• Presentation software

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– Web site creation and management software
– Spreadsheet software
– Database management software

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• Photo editing software
• Multimedia authoring software
• Accounting software
• Information management software

XP
What is the user interface?
• Controls how you
enter data and
commands and
how information
displays
• Types of user
interfaces include
command line and
graphical.
p. 1.12
User Interface

XP
p. 1.12
User Interface
What is a graphical user interface (GUI)?
• Uses visual images such as icons
 Icons represent
programs,
instructions, or
some other
objects
icons
icons
p. 1.12 Fig. 1-13

XP
Architecture or configuration is the design of
the computer.
As in, what does the computer consist of?
Specification is the technical detail about each
component.
As in, how big is the monitor?

XP
Processing Hardware
• The motherboard is the
main electronic
component of the
computer
• The microprocessor is
one of the most
important pieces of
processing hardware on
the motherboard
• Cards are removable
circuit boards

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Processing
Microprocessor, also referred to
as processor or CPU (Central
Processing Unit
RAM - Random Access Memory
 Volatile

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Input and Output
• The data or instructions you type into the
computer are called input
• The result of the computer processing your input
is referred to as output and also referred to as
information.
• Peripheral devices accomplish input and output
functions

XP
Input Devices
• You use an input device, such as a keyboard or a
mouse, to input data and issue commands
– Keyboard
– Pointing device
• Controls the pointer
• Mouse
• Trackball
• Touch pad
• Pointing stick
– Scanner
– Touch Screen
– Pen Input

XP
Output Devices
• Output devices show you
the results of processing
data
– Monitor
• Flat panel
• LCD
• CRT
– Printer
• Laser
• Inkjet
• Dot matrix

XP
Data Representation
• Binary digits (bits)
• A series of eight bits is called a byte
• ASCII
– American Standard Code for Information Interchange

XP
Storage Measurements
 Byte = one character
 Kilobyte = approximately 1000 characters
 Megabyte = approximately one million characters
 Gigabyte = approximately one billion characters
 Terabyte = approximately one trillion characters

XP
• Five basic types of data are represented in the
computer.
– Numeric
– Character
– Visual
– Audio
– Instructional
Storage
Data RepresentationData Representation

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Data RepresentationData Representation
How do computers represent data?
 Most computers are digital
 Recognize only two discrete states:
on or off
1 1 1 1 1
0 0 0 0 0
on
off
p. 4.13
Storage

XP
• A digital computer’s circuits are binary.
• The circuits can exist in either one of two electrical
states, normally represented by 0 and 1, that is, OFF
or ON.
• Each 1 or 0 is called a binary digit or bit and are the
basis for measurement of storage.
• Each character (letter, number, etc.) equals one
byte.
• These bytes can add up, especially when
representing images (graphics).
Storage

XP
• Consider the math – 1 byte = 1 character, 5
characters per word, 400 words per page, 200
pages per book.
– CD = 700,000,000 bytes = 1,750 books
– DVD = 4,200,000,000 bytes = 10,500 books
– Hard Drive (small in lab) = 6,000,000,000 bytes =
15,000 books
– Hard Drive (newer) = 100,000,000,000 bytes =
250,000 books
Storage

XPStorage
Representing Symbols and Text
• Each letter and symbol in a text document
must be translated into a binary number
for storage in the computer.
• Symbols and Text
– Includes characters, punctuation,
symbols representing numbers.
– Each symbol can be assigned a
numeric value
• Two standardized sets of codes for
symbols:
– ASCII (American Standard Code for
Information Interchange)
– EBCDIC (Extended Binary Coded
Decimal Interchange Code)
• Developed by IBM for use on their
mainframe computers.

XP
• The ASCII code, or simply ASCII, is used by virtually all other
computers in the United States and Europe as well. All
personal computers use the ASCII code.
Storage
 0 - 0110000
 1 - 0110001
 2 - 0110010
 3 - 0110011
 4 - 0110100
 5 - 0110101
 6 - 0110110
 7 - 0110111
 8 - 0111000
 9 - 0111001
 : - 0111010
 A - 1000001
 B - 1000010
 C - 1000011
 D - 1000100
 E - 1000101
 F - 1000110
 G - 1000111
 H - 1001000
 I - 1001001
 J - 1001010
 K - 1001011
 a - 1100001
 b - 1100010
 c - 1100011
 d - 1100100
 e - 1100101
 f - 1100110
 g - 1100111
 h - 1101000
 i - 1101001
 j - 1101010
 k - 1101011
 Ctrl+@(NULL) - 0000000
 Ctrl+A - 0000001
 Ctrl+B - 0000010
 Ctrl+C - 0000011
 Ctrl+D - 0000100
 Ctrl+E - 0000101
 Ctrl+F - 0000110
 Ctrl+G(Bell) - 0000111
 Space - 0100000
 Delete - 1111111
A partial listing of the ASCII character set

XPStorage
 A new coding system has recently been developed called
UNICODE.
 Unicode provides a unique number for every character, no
matter what the platform, no matter what the program, no
matter what the language.
 Why UNICODE?
 No single encoding could contain enough characters: for
example, the European Union alone requires several
different encodings to cover all its languages and what
about Asian languages with all there characters.
 Even for a single language like English no single encoding
was adequate for all the letters, punctuation, and
technical symbols in common use.

XPStorage
 Digitized picture of a tiger.
Representation of Images

XPStorage
 Black and white pixels are either 0 or 1.
0001000000000000000000000000000000000000010101
0100000000000000100000000000000000000000000101
0110000000000000100000000000000000000000000011
1010101000000000010000000000000000000000000011
1001000000000000101100000000000000000000000101
0100010000000000011110000000000000000000000111
0100100100000000011111010101011100000000000011
0001000000000000111101110111111101000000001011
0000101001000001101111101111110110000000001111
0000010100000000111110111101011101000000000111
0000010100100011101010101011010000000000010111
0000001010100000011101010101101010100000011111
0000010110000001010100100000000000000000001110
0000000000011001010100000000000000000000001111
0000000000010110010100000000000000000000101111
0010010101010100100101010000000000000001011111
1000001111110100101101110101011000000010110111
1001001111010111111111110101101101011111111111
0110010111110111111111111111111101111110111111
1010101101111111111111111111111111111111111111
1010000111011111111111111111111111111111111111
0101010011111111111111111111111111111111111111
0110000101011111111111111111101111110011110101
0101111011111111111111111111111011010101110101
1010101011111111111111111010110111101111011111
0000001011111111111101011101101001111110101010
0000001011111111111101111111110010111101101010
0000000111111010111110111011101001111110101010
0000000111111111111111010111111101111110111011
0000101111101101010110000101111111111111101011

XPStorage
• Gray-Scale:
– Each pixel contains a value representing some shade
of gray.
– The more shades of gray possible, the more
memory will be needed.
• 4 shades of gray needs 2 bits per pixel:
– 00, 01, 10, 11
– 000, 001, 010, 011, 100, 101, 110, 111
– 000000, 000001, … 111110, 111111

XPStorage
• Representing colors in
pictures takes even
more bits than gray-
scale.
• The more colors the
more bits and thus
more:
Memory is required
Processing power is required
A better graphics card is required

XP
Storage
– Fact: All types of information are stored in binary form.
– Problem: The computer has no way of discerning
between types unless a file is marked in some
manner for identification by the operating
system.
– Files are marked as to type with unique icons
and have an extension that indicates file type.
(e.g., .doc, .txt, .html, .xls, .ppt, .wav, .jpg and so
forth)

XP
Storage
Windows files showing their icons and extensions

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Memory
• Random access memory (RAM)
– Volatile memory
– SDRAM
• Cache memory (RAM cache or CPU cache)
• Virtual memory

XP
Memory
• Read-only memory (ROM)
– BIOS
– Nonvolatile memory
• Complementary metal oxide semiconductor
memory (CMOS)
• Semi permanent memory

XP
Method of Access
 Sequential access – retrieve data in order.
 Example of media- magnetic tape
 Direct or random access – go directly to required data.
 Example of media- magnetic disk, CD-Rom, DVD

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Storage Media
• A computer file is a named collection of stored
data
• An executable file contains the instructions that
tell a computer how to perform a specific task
• A data file is created by a user

XP
Storage Media
• Magnetic media
– Hard disk
– Tape
– Floppy disk

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Hard Drive
 Consists of one or more rigid metal platters
coated with a metal oxide material that
allows data to be magnetically recorded on
the surface of the platters
 The number of platters permanently
mounted on the spindle of a hard disk
varies.

XP
Storage Media
• Optical storage device
– CD
– DVD
– CD-R
– CD-RW
– CD-ROM

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Storage Media
• Flash memory
– Flash memory cards
– USB flash storage device
– USB drive (flash drive)

XP
Data Communications
• The transmission of text, numeric, voice, or video
data from one computer to another or to a
peripheral device is called data communications
– Sender and receiver
– Channel
– Protocol
– Device driver (driver)

XPComponents of Data Communications
The four essential components of data
communications are:
• Sender
• Channel
• Receiver
• Protocols

XPData Communication
A sender is the computer that originates the
message.
The message is sent over a channel, such as a
telephone
The receiver is the computer at the message’s
destination.
Protocols are the rules that establish the transfer
of data between sender and receiver.

XP
New Perspectives on Essential Computer
Concepts
49
Networks
A network connects one computer to
other computers and peripherals.
In a local area network (LAN), computers
and peripherals are close to each
other.

XP
Concepts
50
Networks
Each computer that is part of the network
must have a network interface card and
network software.
Then it becomes a workstation.
Any device connected to the network is
called a node.

XP
Telecommunications
Telecommunications is communicating
over a telephone. In the
telecommunications process, the
modem converts digital signals to
analog signals at the sending site and a
second modem converts them back at
the receiving site.

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Telecommunications

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The Internet
The Internet is the world’s largest
network.
E-mail and the World Wide Web are two
benefits of the Internet.

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A hyperlink is a place on a Web
page allowing you to connect to a
particular file.
http://www.course.com/newperspe
ctives
The Internet

XP
Concepts
55
The Internet
A Web browser is
the communications
software that
allows you to
navigate the
WWW.

XP
Networks
• A network connects one computer to other
computers and peripheral devices, enabling you
to share data and resources with others
• Network interface card (NIC)
• LAN
• WAN
• WLAN
• PAN
• WiMax

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Telecommunications
• Telecommunications means communicating
over a comparatively long distance using a phone
line or some other data conduit
– Modem
• Digital and analog signals
– DSL

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The Internet
• The Internet is the
largest network in the
world, connecting
millions of people
– Electronic mail
– World Wide Web
• Web page
• Web site

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Security Threats on Your Computer
• Security refers to the steps a
computer owner takes to
prevent unauthorized use of
or damage to the computer
– Malware
• Viruses
– Antivirus software
• Spyware
• Adware
• Firewall
• Phishing
• Pharming

Essential Computer Concepts

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