introduction to computers.pptx

8/10/2019 Introduction to Computers.pptx

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Introduction to Computers

Presented By

RAJANI TYAGI


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Computer Basics

Introduction

The two basic computer components

Hardware Software

Other common terms


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Introduction

A computer is a fast electronic machine that

1) takes in data and instructions (input)

2) works with the data (processing)

3) puts out information (output)

The computer as we know it is a group ofpieces of hardware put together to get a job

done faster


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It can quickly store, retrieve and process large

amount of data. It can perform complex and

repetitive procedure quickly

It has three main components:-

1. C.P.U.(central processing unit)

2. Memory3. Input & Output device


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1. C.P.U.:-It is the brain of the computer.

This is the component that actually executesinstructions organized in programs which tellsthe computer what to do.

2. Memory:-It enables a computer to store dataprograms and intermediate results.

3. Input device:-these devices are the mediumthrough which data and instructions are enteredinto a computer. Eg.Keyboard, mouse, scanneretc.

4. Output device:-these devices display the resultsproduced by the computer. Eg. Monitor, printeretc


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Data and Information Data is facts and figures or programs that we entered

as input to computer system.

Data can be in the form of numbers, characters,symbols, or even pictures.

It can be any object,behavior,condition etc. forexample-personal details of employees, Grades of astudent, picture of a person etc

EXAMPLE:-If we want to calculate gross salary of anemployee than name of the employee, designation,

department, basic salary etc. will be provided toapplication and they will be treated as meaningfulinformation on final outcome .


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Information can be said the final resultachieved after processing the data

A collection of these data which conveys some

meaningful idea is information. Ex:-if we consider the above example their

name, designation , department ,basic salary,

HRA,TA,PF of an employee is data but afterprocessing these data item we get pay slip.these pay slips referred to as information.


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characteristics of computer system

The characteristics of computer are

1.Speed

2. Accuracy3. Automatic

5. Storage

6. Reduction of cost


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The two basic parts of a computer system

Hardware

The hardware is thepart of the computer

you can touch and see

Software

The software is a part ofthe computer you

cannot touch but is veryimportant. Thesoftware is all theprogramming thatmakes the computerrun; controllingeverything that thecomputer does


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Common computer hardware

Monitor : The monitor is the display screen .

Keyboard : The keyboard is used to typeinformation into the computer or input

information.

Mouse : The Mouse is the small hand helddevice that attaches to the computer. It mayhave two or three buttons. The mouse is usedto move the cursor (pointer) on the computerscreen


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The Central Processing Unit (CPU)

The most important part, also called the

Central Processing Unit or CPU, is a box that

includes many pieces that are not particularly

relevant to us at this time. These pieces, inside

of the box, perform the jobs of the computer.

Processor is the part of the computer thatactually does the computations.


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Peripherals

A peripheral is an object attached to the

computer to help it perform some necessary

assignments none of the other parts can

handle. The most used peripherals are the

printer, a digital camera, a scanner, a

projector, an external drive


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Software

As described earlier, the software is a part of thecomputer you cannot touch but is veryimportant. The software is all the programming

or instructions that makes the computer run;controlling everything that the computerdoes. There are two kinds of software that helpthe computer run:

Operating Systems

Applications


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An Operating Systemis the base program on acomputer. It tells the computer how to work oroperate. The operating system also allow you to loadother programs that do specialized tasks on to your

computer. An operating system(OS) is a set ofprogramsthat manages computer hardwareresources, and provides common services for

application software.ex.

Microsoft Windows
http://en.wikipedia.org/wiki/Computer_programhttp://en.wikipedia.org/wiki/Computer_hardwarehttp://en.wikipedia.org/wiki/Application_softwarehttp://en.wikipedia.org/wiki/Application_softwarehttp://en.wikipedia.org/wiki/Computer_hardwarehttp://en.wikipedia.org/wiki/Computer_program


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Applications are programs put onto the

computer to do specialized tasks.

ex.

Word and WordPerfect

(used to type letters and more complicated

documents)

Explorer

(used to explore the Internet)


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Microsoft Windows is the operating system found

on most personal computers. As an operating

system Windows manages all that the computerdoes. Through Window's main screen called the

"Desktop"you can get to everything your

computer can do.


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Windows Topics:

Icons

The "Start" button

Menus

The taskbar

Adjusting windows Using "My computer"
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Icons

On the desktop screen you will see severalsmall pictures. These pictures are called

"Icons." The "My Computer" picture below

is an example of an icon. Double clicking

the left mouse button on an Icons will start

the programs it represents. Another way to

start programs is by using the Start

button.


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The "Start" button

The "Start"button is probably the most

used part of the Windows Desktop. The

start button is where you access all the

programs on the computer. When you click

on the "Start"button you will be shown amenu of the major computer headings.

These headings provide access to the major

programs on your computer.


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Menus

When you clickon the "Start"button a

menu with options will appear. Moving themouse over the items in the menu causes

them to highlight. Clickingon a highlighted

item will open that program.


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The taskbar In the bottom section of the screen, there is (or there may

be) a long object. It is called the Taskbar: On the left side of the taskbar, there is an object labeled

Start or . The appearance of this object depends on thetype of Windows you are using but it plays the same role.

Windows has the ability to run several programs at onceand to easily switch back and forth between runningprograms. All programs currently running are shown onthe windows "taskbar." The taskbar is a gray bar withpictures on in it that runs across the very bottom of thescreen. The taskbar can be recognized by the "Start"

button located on its left hand side and the clock on itsright. To switch between programs that are running at thesame time, click on the program buttons shown on thetaskbar. This is demonstrated below.


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Adjusting a window's size Common to all Windows programs is the

ability to adjust the shape and size of thewindow you are working in. Some of the

ways you can change a window includes;

moving, closing, maximizing, minimizing andrestoring it. The following diagram and chart

explains how to adjust a window.


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Using my computer The "My Computer" program is a tool that lets

you see everything that is stored on yourcomputer. It is useful for finding, organizing

and storing files on your computer. Files

represent stored information that you havenamed. Think of "My Computer" as a filing

cabinet for your computer.

You can open the "My Computer" program bydouble clickingon the "My Computer" icon on

the "desktop" as shown below.


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The icons in the" My Computer" window represent all the drives,folder and fileson your computer.

Drives:

Drives are like filing cabinets for computer files. To see what isstored on a drive double click on its icon and a list of files andfolders will appear. These files and folders will be arrangedalphabetically. To open any of these files double click on them.

The A: drive icon opens files saved on a floppy disk. You may onlyopen this drive when you have put a floppy disk into the drive slot

of the computer. The C: drive icon on most home computers represents the hard

drive. This is the drive where all the programs that your computerruns are stored. You can also store files that you have created onthis drive. If you do not think that the C: drive is your hard drive,look for a drive that has the same picture for an icon.

The D: drive icon represents the CD-ROM drive. Double clicking onthis icon will show you all the files stored on a CD-ROM.


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Folders:Folders help you organize your files by dividing up adrive into alphabetically organized sections. Doubleclicking on a folder will open it. Each folder can also

hold other folders and files.

Files:Files are information stored by a program. For example

a file created in "WordPerfect" will be saved with theending ".wpd." Double clicking on a file will open it.


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Internet Topics:

What is the Internet?

What is the Internet used for?

Web addresses

Web Browsers Connecting to the Internet

Introducing Internet explorer

The menu bars options

The Navigation Bars Option

The location bar

Favorites
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What is the Internet?The Internet is a world wide collection of networked

computers which are able to exchange information with

one another very quickly. The computers that make upthe Internet exchange information using the same cablesand general technology that your home phone uses. Mostpeople use the Internet in two ways, e-mail and the WorldWide Web.

History lesson:The Internet was originally developed by university researchersand was funded by the United States DefenseDepartment. The Defense Department wanted its computernetwork to be able to communicate effectively even if some

sections were knocked out. The Internet provides manypossible pathways for information to travel betweencomputers.


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Advantages

Communication:

The foremost target of internet has always been the communication. And

internet has excelled beyond the expectations .Still; innovations are going

on to make it faster, more reliable. By the advent of computers Internet,our earth has reduced and has attained the form of a global village.

Now we can communicate in a fraction of second with a person who is

sitting in the other part of the world. Today for better communication, we

can avail the facilities of e-mail; we can chat for hours with our loved ones.There are plenty messenger services in offering. With help of such

services, it has become very easy to establish a kind of global friendship

where you can share your thoughts, can explore other cultures of different

ethnicity.


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InformationInformation is probably the biggest advantage internet isoffering. The Internet is a virtual treasure trove ofinformation. Any kind of information on any topic underthe sun is available on the Internet. The search engines like

Google, yahoo is at your service on the Internet. You canalmost find any type of data on almost any kind of subjectthat you are looking for. There is a huge amount ofinformation available on the internet for just about everysubject known to man, ranging from government law and

services, trade fairs and conferences, market information,new ideas and technical support, the list is end less.


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EntertainmentEntertainment is another popular raison d'tre why many peopleprefer to surf the Internet. In fact, media of internet has becomequite successful in trapping multifaceted entertainment factor.Downloading games, visiting chat rooms or just surfing the Web are

some of the uses people have discovered. There are numerousgames that may be downloaded from the Internet for free. Theindustry of online gaming has tasted dramatic and phenomenalattention by game lovers. Chat rooms are popular because userscan meet new and interesting people. In fact, the Internet has beensuccessfully used by people to find life long partners. When people

surf the Web, there are numerous things that can be found. Music,hobbies, news and more can be found and shared on the Internet.


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ServicesMany services are now provided on the internet such as

online banking, job seeking, purchasing tickets for yourfavourite movies, hotel reservations.

E-CommerceEcommerce is the concept used for any type of

commercial business deals that involves the transfer of

information across the globe via Internet. It has become a

phenomenon associated with any kind of shopping,

almost anything. You name it and Ecommerce with its

giant tentacles engulfing every single product and servicewill make you available at your door steps. It has got a real

amazing and wide range of products from household

needs, technology to entertainment


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DisadvantagesTheft of Personal information

If you use the Internet, you may be facing grave danger as

your personal information such as name, address, credit cardnumber etc. can be accessed by other culprits to make your

problems worse.

Spamming:

Spamming refers to sending unwanted e-mails in bulk, which

provide no purpose and needlessly obstruct the entire

system. Such illegal activities can be very frustrating for you,

and so instead of just ignoring it, you should make an effort to

try and stop these activities so that using the Internet can

become that much safer.Virus threat

Virus is nothing but a program which disrupts the normal

functioning of your computer systems..


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Web addresses

As described earlier the Web is a collection of documents (Webpages) stored on computers around the world. Just like everyhouse has a postal code, each Web page has an address describingwhere it can be found. On the Web these addresses are calledURLs. Each URL has several parts which can be demonstrated using

the address: http://www.google.com

http:// This part of the address indicates that it is a Webpage. www.This indicates that the Web page you are looking at ispart of the World Wide Web. google.comThis part of the addressis the domain name and indicates the unique address of a Website. The domain name also often indicates what the site is about,for example www.dog.comis a Web site about dogs.

The "/" symbol indicates you have moved into a specific directoryin the Web sites. .
http://www.dog.com/http://www.dog.com/http://www.dog.com/


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Web browsers Web browsers are programs used to explore the

Internet. There are many Web browser programsavailable including Netscape Navigator, Internet

Explorer and Opera. Internet Explorer is the

Internet browser made by Microsoft and comes

with Windows operating system.


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Connecting to the Internet

To connect to the Internet you must first open your Internetbrowser.

To open your Internet browser :

Left clickon the "Start"button at the bottom left of your

screen.

In the menu that appears move the mouse over the word"Programs." A new menu will appear showing variousprograms on your computer.

Look for the following menu item and left clickon it,Internet explorer will begin to run.


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Introducing Internet Explorer There are four main parts to your web

browser, a Menu Bar, a Navigation Bar, aLocation Bar, and a Display Window


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Data communication

Fundamental characteristic of data

communication

Data communication component

Data representation

Data flow

Categories of network


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The acronym used to remember

these layers is: All People Seem

To Need Data Processing.


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Physical Layer


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The physical layer is concerned with the interface tothe transmission medium.

At the physical layer, data is transmitted onto themedium (e.g. coaxial cable or optical fiber) as a stream

of bits. The physical layer defines the electrical, mechanical,

procedural, and functional specifications for activating,maintaining, and deactivating the physical link

between end systems Devices:-

Hubs, Fast Ethernet, Token Ring Hardware


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Data link layer


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This layer is responsible for providing reliable

transit of data across a physical link.

The data-link layer is subdivided into two sub

layers:

the logical link control (LLC) sub layer

the media access control (MAC) sub layer

X.25, 802.3, 802.3, 802.5/Token Ring,


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The LLC sub layerprovides support for

connections between applications running on a LAN

For multiple stations to share the same medium and still uniquely identify

each other, the MAC sub layer defines a hardware, or data-link address called

the "MAC address".

The MAC sub layerprovides orderly access to the LAN

medium

k


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Network Layer


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the establishment, maintenance, and orderlytermination of virtual circuits

transport fault detection and recovery

Transport Layer:Responsible for breaking the

data into segments, establishing an end-to-end logical connection between machines,and providing for error handling.


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Packet switching


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Packet switching


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Message Switching

Message Switching, also known as store-and-

forward switching, refers to a switching

technique involving transmission of messagesfrom node to node through a network. The

message is stored at each node until such time

as a forwarding path is available.


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What you have seen in this example is anexample of a store and forward network. Inthis scheme, messages are received andstored while a route to or closer to theirdestination is being determined. Once theroute has been established, then the messageis sent to either its final destination or another

intermediate storage and forwarding point.


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The transmission of binary data across a linkcan be accomplished in either parallel or serial

mode .

In parallel mode , multiple bits are sent witheach clock tick .

In serial mode , 1 bit is sent with each clock

tick .


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One way to send parallel data

3 ways to send serial transmission


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introduction to computers.pptx

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