Essential Computer Concepts

FIRST COURSE

EssentialComputerConcepts

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 andUNICODE codes

• Define memory and storage

• Examine image representation

• Identify the hardware and software that are usedfor data communications and to establish a networkconnection

XPObjectives

• Explain how Internet access, e-mail, and theWorld Wide Web affect the use of computers

• Describe potential security threats to computersand protection methods

• Discuss the types of system software and theirfunctions

• Identify popular application software

• Describe how data is shared among differenttypes of application software

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New Perspectives on Microsoft Office 2007: Windows XP Edition 4

What Is a Computer?

• A computer is an electronic device that acceptsdata and instructions from a user, manipulatesthe data according to the instructions, displaysthe information in some way, and stores theinformation 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.


XPHow Does A Computer Know What To Do?

• It must be given a detailed set of instructionsthat tell it exactly what to do.

• These instructions are called a computerprogram, or software.


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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

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Types of Computers

Personal Computers

PDA

Super Computers

DesktopNotebook

Tablet PC

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Computer Systems

• Includes computer hardware and software– Hardware refers to the physical components

of a computer

– Software refers to the intangible componentsof a computer system, particularly theprograms the computer needs to perform aspecific task

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System Software

• System softwaremanages thefundamental operationsof your computer

– Operating system• System resource

• Multitasking

– Utilities

– Programming Languages

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Application Software

• Application software enables you to performspecific computer tasks, such as documentproduction, spreadsheet calculations, anddatabase 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

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What is the user interface?

• Controls how youenter data andcommands andhow informationdisplays

• Types of userinterfaces includecommand line andgraphical.

p. 1.12

User Interface

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p. 1.12

User InterfaceWhat is a graphical user interface (GUI)?

• Uses visual images such as icons

Icons representprograms,instructions, orsome otherobjects

icons

icons

p. 1.12 Fig. 1-13

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Architecture or configuration is the design ofthe computer.

As in, what does the computer consist of?

Specification is the technical detail about eachcomponent.

As in, how big is the monitor?


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Processing Hardware

• The motherboard is themain electroniccomponent of thecomputer

• The microprocessor isone of the mostimportant pieces ofprocessing hardware onthe motherboard

• Cards are removablecircuit boards

XPProcessing


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 thecomputer are called input

• The result of the computer processing your inputis referred to as output and also referred to asinformation.

• Peripheral devices accomplish input and outputfunctions

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Input Devices

• You use an input device, such as a keyboard or amouse, to input data and issue commands

– Keyboard

– Pointing device• Controls the pointer

• Mouse

• Trackball

• Touch pad

• Pointing stick

– Scanner

– Touch Screen

– Pen Input

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Output Devices

• Output devices show youthe results of processingdata

– Monitor• Flat panel

• LCD

• CRT

– Printer• Laser

• Inkjet

• Dot matrix

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Data Representation

• Binary digits (bits)

• A series of eight bits is called a byte

• ASCII

– American Standard Code for Information Interchange

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Storage Measurements

Byte = one character

Kilobyte = approximately 1000 characters

Megabyte = approximately one million characters

Gigabyte = approximately one billion characters

Terabyte = approximately one trillion characters

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• Five basic types of data are represented in thecomputer.

– Numeric

– Character

– Visual

– Audio

– Instructional

Storage

Data RepresentationData Representation

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Data RepresentationData RepresentationHow 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

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• A digital computer’s circuits are binary.

• The circuits can exist in either one of two electricalstates, normally represented by 0 and 1, that is, OFFor ON.

• Each 1 or 0 is called a binary digit or bit and are thebasis for measurement of storage.

• Each character (letter, number, etc.) equals onebyte.

• These bytes can add up, especially whenrepresenting images (graphics).

Storage

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• Consider the math – 1 byte = 1 character, 5characters per word, 400 words per page, 200pages 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

XPStorageRepresenting Symbols and Text

• Each letter and symbol in a text documentmust be translated into a binary numberfor storage in the computer.

• Symbols and Text

– Includes characters, punctuation,symbols representing numbers.

– Each symbol can be assigned anumeric value

• Two standardized sets of codes forsymbols:

– ASCII (American Standard Code forInformation Interchange)

– EBCDIC (Extended Binary CodedDecimal Interchange Code)

• Developed by IBM for use on theirmainframe computers.

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• The ASCII code, or simply ASCII, is used by virtually all othercomputers in the United States and Europe as well. Allpersonal 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 calledUNICODE.

Unicode provides a unique number for every character, nomatter what the platform, no matter what the program, nomatter what the language.

Why UNICODE? No single encoding could contain enough characters: for

example, the European Union alone requires severaldifferent encodings to cover all its languages and whatabout Asian languages with all there characters.

Even for a single language like English no single encodingwas adequate for all the letters, punctuation, andtechnical symbols in common use.

XPStorage

Digitized picture of a tiger.

Representation of Images

XPStorage

Black and white pixels are either 0 or 1.000100000000000000000000000000000000000001010101000000000000001000000000000000000000000001010110000000000000100000000000000000000000000011101010100000000001000000000000000000000000001110010000000000001011000000000000000000000001010100010000000000011110000000000000000000000111010010010000000001111101010101110000000000001100010000000000001111011101111111010000000010110000101001000001101111101111110110000000001111000001010000000011111011110101110100000000011100000101001000111010101010110100000000000101110000001010100000011101010101101010100000011111000001011000000101010010000000000000000000111000000000000110010101000000000000000000000011110000000000010110010100000000000000000000101111001001010101010010010101000000000000000101111110000011111101001011011101010110000000101101111001001111010111111111110101101101011111111111011001011111011111111111111111110111111011111110101011011111111111111111111111111111111111111010000111011111111111111111111111111111111111010101001111111111111111111111111111111111111101100001010111111111111111111011111100111101010101111011111111111111111111111011010101110101101010101111111111111111101011011110111101111100000010111111111111010111011010011111101010100000001011111111111101111111110010111101101010000000011111101011111011101110100111111010101000000001111111111111110101111111011111101110110000101111101101010110000101111111111111101011


XPStorage

• Gray-Scale:

– Each pixel contains a value representing some shadeof gray.

– The more shades of gray possible, the morememory will be needed.

• 4 shades of gray needs 2 bits per pixel:– 00, 01, 10, 11

• 8 shades of gray needs 3 bits per pixel:– 000, 001, 010, 011, 100, 101, 110, 111

• 64 shades of gray needs 6 bits per pixel:– 000000, 000001, … 111110, 111111

XPStorage

• Representing colors inpictures takes evenmore bits than gray-scale.

• The more colors themore bits and thusmore:

Memory is required

Processing power is required

A better graphics card is required


XPStorage

– Fact: All types of information are stored in binary form.

– Problem: The computer has no way of discerningbetween types unless a file is marked in somemanner for identification by the operatingsystem.

– Files are marked as to type with unique iconsand have an extension that indicates file type.(e.g., .doc, .txt, .html, .xls, .ppt, .wav, .jpg and soforth)

XPStorage

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

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Memory

• Read-only memory (ROM)

– BIOS

– Nonvolatile memory

• Complementary metal oxide semiconductormemory (CMOS)

• Semi permanent memory

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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 thattell a computer how to perform a specific task

• A data file is created by a user

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Storage Media

• Magnetic media

– Hard disk

– Tape

– Floppy disk

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Hard Drive

Consists of one or more rigid metal platterscoated with a metal oxide material thatallows data to be magnetically recorded onthe surface of the platters

The number of platters permanently

mounted on the spindle of a hard disk

varies.

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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)

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Data Communications

• The transmission of text, numeric, voice, or videodata from one computer to another or to aperipheral device is called data communications

– Sender and receiver

– Channel

– Protocol

– Device driver (driver)

XPComponents of Data Communications

The four essential components of datacommunications are:

• Sender

• Channel

• Receiver

• Protocols


XPData Communication

A sender is the computer that originates themessage.

The message is sent over a channel, such as atelephone

The receiver is the computer at the message’sdestination.

Protocols are the rules that establish the transferof data between sender and receiver.


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New Perspectives on Essential ComputerConcepts

49

Networks

A network connects one computer toother computers and peripherals.

In a local area network (LAN), computersand peripherals are close to eachother.

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50

Networks

Each computer that is part of the networkmust have a network interface card andnetwork software.

Then it becomes a workstation.

Any device connected to the network iscalled a node.

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Telecommunications

Telecommunications is communicatingover a telephone. In thetelecommunications process, themodem converts digital signals toanalog signals at the sending site and asecond modem converts them back atthe receiving site.

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Telecommunications

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The Internet

The Internet is the world’s largestnetwork.

E-mail and the World Wide Web are twobenefits 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/newperspectives

The Internet

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55

The Internet

A Web browser is

the communicationssoftware thatallows you tonavigate theWWW.

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Networks

• A network connects one computer to othercomputers and peripheral devices, enabling youto share data and resources with others

• Network interface card (NIC)

• LAN

• WAN

• WLAN

• PAN

• WiMax

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Telecommunications

• Telecommunications means communicatingover a comparatively long distance using a phoneline or some other data conduit

– Modem

• Digital and analog signals

– DSL

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The Internet

• The Internet is thelargest network in theworld, connectingmillions 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 acomputer owner takes toprevent unauthorized use ofor damage to the computer– Malware

• Viruses

– Antivirus software

• Spyware

• Adware

• Firewall

• Phishing

• Pharming

Education

Essential Computer Concepts