Email stand for Electronic Mail.It is the exchange of massages and files through Internet.
Messages and files through way of sending messages anywhere in the world.The sender
and receiver may be sent to multiple recipients.Email facility is provided by many Internet
service providers or specialized websites.Yahoo,Hotmail and gmail are examples of
popular email providing websites.
Working of Email:-
An email program is used to create,send and receive emails.It is also known as email 
client.When the user sends an email message,,the computer connects to an email server
and transmits a copy of the message to that server.Email server is a host computer on the 
Internet that is used to send and receive emails.The email server receives the message
and finds out the email server  where that email is to be sent.It connects to that server and
transmits another copy of the message.
Email Attachment:-
An email message can also contain attachments.Attachments is a process of sending
connecting files withemail massage. Any.Any type of file can be attached to email such as documents,spreadsheets,audio and video etc.MIME is an Internet protocol that supports
email attachments.It stands for Multi purpose Internet Mail Extension. Different websites
provide Different file size that can be attached with an email message.
Advantages and Uses of Email:-
Some  advantages of email are as follow:
*It is very fast and timely.
*It is very cheap and inexpensive.
*People can send and receive massage anywhere in the world.
*People can share your information among different people.
*It is possible to send and receive email through mobile phone.
*Email gives us the facility to send picture, sounds and videos.
Limitations/Disadvantages of Email:-
Some limitations of email are as follows:
Lack of Privacy:-
email dose not provide high privacy.It passes from one system to other via different
networks.System administrator of a network or a hacker can read the contents of emails.
Junk Email:-
Junk email is an unwanted email.It is also known as spam.A person may send such email
that the receiver dose not want to read.Sometimes,junk email are in such number that it fills
the space of email account.
spreading of Virus:-
Most of the viruses are speared through email messages.Virus can speared if the user opens
an email containing a virus.
No Emotions:-
An email message connote express emotions properly.The receiver cannot view facial
expression or voice of the sender.He may also interpret a humorous message wrongly.
Possible Delay:-
Email is read when the user connects to the Internet and checks email account.An urgent 
message may be ignored or delayed if a person dose not check his email account soon.
Communications Problems:-
E mail may not be delivered successfully due to communication errors.
Email Address:-
Every email has different address.An email address usually has two parts which are
separated by symbol @.These parts are as follows:
*User ID          *Identity of email service
Example:-
myemail@hotmail.com
my email:-
myemail is called user ID.It is used to sign into email service. 
@:-
It is "at" sign.It separates account ID from name of Email service provider.
hotmail.com:-
It indicates the email service provider.

It is a  collection of documents or web pages stored on computers permanently connected
with internet around the world.A web page is a document that may include text,graphics,
sound and video etc. These web pages are connected to one another hyperlinks. Web.Web
pages are also famous as hypertext documents.Anyone can view web pages through a web
browser.A collection of related web pages is called website.each website  has unique address.
Website are stored on a host computer on the Internet.These computers are known as web
server.The process of launching a web page is called publishing the page.
Purpose and Uses of  WWW. The uses of  WWW (world wide web) are as follows:

Advertisement:-
Manufacturers use WWW to provide information of products.

Shopping:-  
It is possible for users to buy an item using WWW.You can see products and prices and
even order them by using your credit card etc.Some websites are very nice if you buy
some thing they provide home delivery with out any charge. 

Flight Information:-
It is used to provide the latest and quick information on flights arrival and departures with
out wasting time and you are buy tickets also.

Television Station:-
WWW is used to provide information about the programs,latest news and special events
etc. Some television shows Different events Live on the websites.you are watching live
sports streaming like football tens cricket all most every type of sports you are watching
live.

Celebrities:-
 Important celebrities can contact their fans,provide information about them and send their
pictures.Some time they are chat with friends and video chat also.

Government Authorities:-
Government authorities can provide information about services and facilities for the people.
People see their jobs alerts and much more about government.

News:-
Most newspapers have their websites. Latest news and interviews are provided on the
websites.If you miss any news.you are see this news in their news website.

Encyclopaedia Publisher:-
Online encyclopedias are available. You can find detailed information on any topic in the world.

Search Engines:-
search engine is a website that provide the facility to find the required website on a particular topic.

Medical:-
many sites in the world provide detail information on diseases. You can also consult a panel
 of on-line doctors to get the advise about any medical problems.Today you perches medicine
online with the help of doctor                

Internet is used to find information stored on the computers called hosts or servers.These
computers use a common protocol called TCP/IP for communication.A host computer
 provides information to the people.Today more than 100 million users around the world
connect to the Internet for different purposes.No govt or  organization is the owner of Internet.
Uses of Internet:-
> To access information,news,research,and educational material
> to conduct business.
> To access sources of entertainment such as on line games,magazines etc.
>To shop for goods and services.
>To meet and talk with people around the world in discussion groups or chat rooms.
>To access other computers and exchange files.
>To send messages and receive messages from other connected users.
Internet Working:-
These carriers of network traffic are collectively called Internet backbone.A client computer
accesses data, information and services from different servers.The server computer are also
called host computers in global village.
Impacts of Internet on Society
The impacts of the Internet on the society are as follows:
Globalization
Internet has converted this world into a small global village just like world on our finger tips.
people are connected with one another using the help of Internet.It has provided more 
opportunities of interaction.It also enables people to understands the views of one another.
Folw of Information:-
Internet contains information on all types of topics.People can search information on any
type of topic.Search engines are used to search information on Internet with help of different
search engines like ask,Google,Yahoo etc .Easy access to information has enabled people
to be informed.
Better Understanding with unknown persons:-
Internet is an easy way of communication among people with each other.They can exchange
their views.It has  created better understanding with the different persons  to know each other.
People can understand the views and thinking of one another.It helps in harmony and peace
in the world and world become just like a heaven .
Better Society
The use of Internet has provided many comforts for society.People can perform their duties
easily with out any uncomfortable things .They can sell and buy goods on line in online 
market .They are run their business using the Internet.
Knowledge
Internet is a source of huge information about knowledge.People can get information from
websites. They can interact with different people,scholars and learned persons to get knowledge.

Mail Merge feature in MS Word is used to create one form letter and a data document
that are used to send bulk mailings.For example ,student can create one letter that contains
from fields and then enter the required name and addresses called data source . these are
merged into the main documents letter. the mail merge wizard is used to complete mail merge
process in different ways.

Using Mail Merge
The following procedure is used to create a form letter and merge letter with data list.
1. Select Tools>Letters and mailing>Mail Merge. Mail Merge task pane appears.
2. Choose the type of document to create such as Letters.
3. Click Next : Starting document to move to step 2.
4. Select Use the current document.
5. Click Next:Select recipients to move to step 3.
6. Select Type a new list option.
7. Click Create to create a data source.The New Address List dialog box appears.
8. Perform the following steps to edit New Address LIST:
* Click Customize button.The Customize Address List dialog box appears.
* Select A field and click Delete.
* Click Yes to confirm to delete the field.
* Continue to delete any unnecessary fields.
* Click Rename.The Rename Field dialog box appears.
* Enter the new name for the field in To:field.
* Continue to rename any fields necessary.
* Click OK to close Customize Address List dialog box.
9. enter the necessary data in New Address List dialog box.
10. Click New Entry to enter another record.
11. Click Close after entering all data records.
12. Enter the file name to save the file.
13. Choose the location to save file.
14. Click Save.The Mail Merge recipients dialog box appears and displays all the
Data records in the list.
15. Confirm data list is correct and click OK.
16. Click Next: Write Your Letter to move to step 4.
17. Write a letter in current Word document.
18. Place the cursor where any fields from data record is to be entered.
19. Perform the following steps to insert data from data list.
* Click Insert Merge Fields button.The Insert Merge Fields dialog box Appears.
* Select the fields to insert in the document.
* click Insert.A placeholder appears where information from Data records will appear.
* Repeat these steps to enter information from data record.
20. Click Next: Preview your letters in the task pane after completing the letter.
21. Preview the letters to make sure the information from data record appears correctly.
22. Click Next: Complete the merge>
23. Click Print to print the letters.
24. Click All and click OK in merge to printer dialog box.
25. Click OK to send the letters to the printer.

Microsoft window is the most widely used graphical user interface operating system
for personal computers.Windows uses graphics to make the program easier to use and
sometimes called GUI(Graphical User Interface).All Windows operating systems support
the use of mouse,icons and menus.We can open several applications at the same time and
easily move data from one application to another.The user dose not need to learn complex
command languages.Some important operating systems are follows:
*Windows XP*UNIX*Linux* Mac OS
Evolution of Windows Operating System
Microsoft Windows is developed by Microsoft Corporation.The first successful series of
Windows was Windows 3.x series.Windows 3.x was an operating environment.It provided
a GUI that executed on top of DOS.It replaced the command-line interface with point-and-
click system.Microsoft released window 95 in 1995.It was a complete operating system for
personal computers.Windows 98 was an improved version of window 95.It was released in 
1998.it was more stable than windows 95.It is very popular these days.
Microsoft also concentrated on networking features in windows.it released Windows NT
(new technology) with extensive networking features.All later versions of windows operating
systems are based on NT technology.These include Windows 2000(server and professional)
and Windows XP.
Graphical User Interface(GUI)
Graphical User Interface operating system consists of a visual environment.It is used by the
user to communicate with the computer.It uses Windows,icons,menus and other graphical
objects to issue commands.A menu is a collection of commands.An icon is a small picture that
represents a program.Mouse is the most commonly used input devices in this operating system.
Advantages/Features of GUI
The advantages of GUI are as follows:
Graphical Interface:-
Most of the users like graphical environment.Visual presentation increases the understanding
of the users and they can easily understand the environment.
Easy to Use:-
The Graphical user interface uses buttons, menus and icons etc.These are easy to use because
the user dose not have to remember the commands.For example, the user can close a window
by simply clicking on the cross button on the title bar of the window etc.
Easy to Learn:-
As the interface is full of graphics the user finds it easy to learn as he has the tools are self-
explanatory.
Attractive:-
The color,size and fonts of graphical environment make it more colorful; and attractive.

An operating system is a set of programs that manages all computer components and
operations.A computer cannot do anything without an operating system.Operating system
must be installed on every computer.Users interact with the computer through the operating
system.when computer is turned on, the operating system properly.It manages all operations
on the computer after loading in memory.The following figure shows that an operating system
acts as interface between the user and computer hardware.
Important Operating systems
Some important operating systems are as follows:
* Microsoft windows * Linux * Unix * Mac OS * Solaris
Functions of Operating System
Operating system performs the following functions:
Booting:-
Booting is a process of starting or restarting the computer.Operating system starts the
computer to work.It checks the computer and makes it ready to work
Memory management:-
It is also an important function of operating system.The memory cannot be managed
without an operating system.Different programs and data execute in memory at one time.
If there is no operating ,the programs may mix with each other. The system will not work
properly.
Loading and Execution:-
A program is loaded in the memory before it can be executed.Operating system provides the
 facility to load programs in memory easily and then execute it.
Data Security:-
Data is an important part of computer system. The operating system protects the data stored
on the computer from illegal use modification.
Disk Management:-
Operating system manages the disk space.It manages the stored files and folders in a proper
way.Disk management is most important unit in computer operating system.
Process Management:-
CPU can perform one task at one time.If there are many tasks,operating system decides which
task should get the CPU.
Device Controlling:-
Operating system controls all devices attached to computer.The hardware devices are
controlled with the help of small software called device drivers.
Printing Controlling:-
Operating system also controls printing function.If a user issues two print commands at a time,
it dose not mix data of these files and prints separately.
Providing Interface
User interface is used to interact with computer.User Interface controls how you enter data
and instructions and how information is displayed on the screen.Operating system provides
two types of interfaces for the user.
Graphical User Interface:-
It consists of visual environment to communicate with the computer.Is uses windows,icons,
menus and other graphical objects to issue commands.
Command-line Interface:-
It provides an interface to communicate with the computer by typing commands.

A set of instruction given to the computer to solve a problem is called software.
Software is also called program.Different software's are used to solve different problems.
A computer works according to the instruction written in software.Software is logical
part of a computer.Software cannot be touched.The hardware cannot perform any task
without software.Software is usually stored on hard disk or CDs.It is loaded from the disk
to RAM as and when required.
Types of Software
The main types of software are system software and application software.
System Software:-
System software is set of programs to control and manage the actual operations of a
computer hardware.It controls the usage and allocation of different hardware components.
It enables application programs to execute properly.It controls the basic operations as follows:
* Saving data on disk
* Making computer to work for us
* printing a documents etc.
Types of System Software
Two types of system software are operating system and utility program.
Operating System
An operating system is a set of programs that manages all computer components operations.
A computer cannot do anything without an Operating system.Operating system must be
installed on every computer.Users interact with the computer through the operating system.
Microsoft Windows and Linux are examples of operating system software.
Utility Programs.
A utility program is a type of system software that is used for effective management of
computer system. the user can use utility program to per maintenance tasks related to
different devices and programs. The utility programs to perform maintenance tasks related
to different devices. The utility programs keep the computer system running smoothly.Anti 
virus and file compression software are examples of utility programs.
Application Software
Application software is used to perform various applications on the computer.It helps a
computer user to perform specific tasks.people use application software according to their
needs.It is also known as application package.package. Different software packages are
used on computer to ease the work.The application software uses the operating system in
order to function. The operating system is the base software.The application software runs
on top of the operating system software.
Categories of Application software
The main categories of application software are follows:
Customized Software:-
Customized software is a type of application software that is designed for a particular 
customer or organization.It is developed to meet the exact requirements of a particular
customer or organization.A customized software can be developed by single programmer
or a team of programmers.The cost of customized software is more than package software.
Example:-
A software developed for a particular university is an example of customized software.
Package Software:-
Package software is a type of application software that is developed for sale to the general 
public.It is also known as off-the-shelf software.It enables the people to perform daily
activities.package software is normally developed by expert programmers.
Examples of application software are as follows:
Word Processing:-
word processing software is used to produce letters,applications and other documents.
MS Word is an example of word-processing software.
Spreadsheets:-
Spreadsheet program is used for calculations.It provides worksheets to enter data.A
formulas and built-in functions.It provides the facility to display data using charts and figures.
MS Excel an example of spear sheet software.
Databases
Database is an organized collection of related data that is stored in an efficient and compact
manner.It is used to store information quickly.MS Access and oracle are example of database
software.
Graphics
Graphics software is used to produce advertisements,posters etc.It can also be used to draw
 pictures and figures. Coreldraw and Photo shop are examples of graphic software.
Communication
Communication software is used to communicate with different people using Internet.The 
communication is of different types.The user can communicate by sending email or voice 
mail. MSN Messenger.Outlook Express,mIRC and Internet Explorer are examples of 
communications software.
 

1. Analog computer 2.Digital Computer 3.Hybrid Computer.

 1. Analog computer
 Its output is usually displayed on a meter on a graph. It dose not operate with digital signals.
It has so low memory and fewer functions. It is different to operate and use.It is usually built
for special purposes.It is mainly used in engineering and medicine.
*Examples:-
1.speedometer used to measure the speed of car.
2.Analog clock measures time by the distance traveled by hands of clock around dial.
3. Thermometer is an analog device that measure the length of mercury column.

2.Digital Computer:-
A digital computer processes data in numerical form using digital circuits. It performs 
arithmetic and logic options with discrete values. These values are 0 and 1. Everything is
described in two states of ON and OFF. The digit 1 represents ON and 0 represents OFF
state.The digital computers are very fast. These computers are manufactured in a variety of
size,speeds and capacities. Digital computers are commonly used at homes and in offices etc
.APPLE MACINTOSH and IBM PC are two important digital computers.
*Examples:-
1.Digital watch displays the time that does not very continuously but changes from one
discrete value to the other.
2.Digital scoreboard directly counts discrete values such as the time left to play and the
score of each team.

3.Hybrid Computers:-
A hybrid computers is a combination o both analog and digital computers. A hybrid computer
combines the best characteristics of both the analog and digital computer. It can accept data in
analog and digital form.hybrid computer is faster then analog and digital computer very easy to
use performing well.
*Examples:-
1.Hybrid computer is a devices may calculate patient's heart function, temperature,
blood pressure etc. This measurement can be converted and displayed in digital form.

computer are classified on the basis of size,speed ,processing power and price.however,
the classification of computers is not very straight-forward.the distinction between these
categories is sometimes not very clear. some characteristics overland different categories.
computer can be divided into the following categories:
>microcomputer or personal computer
>minicomputer
>mainframe computer
>super computer
>embedded computer

Microcomputers:-
microcomputer is also called personal computers.It was introduced in 1970.it is designed to
be used by one person at a time.it consists of a processor,memory and one or more input,
output and storage devices.It also often contains a communication device.The price of
personal computer is from several hundreds to several thousand dollars.Most commonly
used personal computers are PC and Apple .PC and its compatible computers used
windows operating systems.The term OC compatible means any personal computer based
on the original IBM personal computer design.Apple computers use Macintosh operating
system. the major types of personal computer are desktop computer and portable computer.

(i)DESKTOP COMPUTERS:-

Desktop computers are the most  common type of personal computer.it is designed in a
way that all its components fit on desk or table.In one model, the system unit is placed 
horizontally on the desktop or table monitor is placed on the table. system unit in tower
model is placed vertically.
(ii)PORTABLE COMPUTER 
portable computer is a personal computer that can be carried from one place to other
easily.Different types of portable computer include notebook computers,tablet PC and
handheld computers.
1:-NOTEBOOK COMPUTERS
Notebook computer is also called laptop computer.It is a portable personal computer that
can be placed on lap easily.It is more expensive than desktop computer.Is is thin and light
weight.It uses less power and can be used with batteries. Only.Only one user can be use
them at a time.A notebook computer can perform the same basic functions as a personal
computer The computing power of modern notebook computers are nearly equivalent to
personal computers.The price of these computers is from $1000 to $2500.
Net Book:-
Netbook is a small,light and inexpensive laptop computers.Is is suited for general computing
and web-based applications.It provides reduced computing power as compared to a full-size
laptop computer.
2:-TABLET PC
Tablet PC is a special type of notebook computer. It is used to writ or draw on screen using
a special digital pen or stylus.Some tablet PCs have an attached keyboard and some allow
the user to connect a separate keyboard.It also supports voice input to enter text and give
instructions by speaking it is used to take notes in lectures, meetings and conferences.
3:-HANDHELD COMPUTERS
Handheld computers is also called palmtop computer.It easily  fits in the hand of the user.
It contains small screen and small keyboard.keyboard. Handheld often use stylus as input
device to enter data.Some handheld computers also support voice input.Handheld computers
usually have no disk drive.The programs and data are stored on chips in the system unit.
Handheld computer is not powerful as compared to desktop and notebook computer.
 USE OF MICROCOMPUTER:-
Micro computer is  the most common type of computer used in the office and at home.It is
also used for business and engineering application. 
Minicomputers:-
 Minicomputer can serve up to several hundreds connected computers simultaneously.
It is normally accessed by users through personal computer or terminal.It is also with a 
monitor and keyboard is called terminal it is also called dumb terminal.It has no processing 
power and cannot work as stand-alone computer.It has to be connected to a server.
EXAMPLES:
Prime 9955
HP 3000
AS 400
VAX 8600 
Mainframe Computers:- 
A mainframe computer is a large computer in terms of price,power and speed.It was 
introduced in 1975.It is more powerful than mini computer.It consists of multiple 
processor.It is specially designed to perform multiple tasks for multiple users simultaneously.
It is designed for high reliability. is is also known as enterprise server or high-ended server.
Mainframe computer can serve several thousand users simultaneously. these computers can 
store  large amounts of data .information and programs.The users access a mainframe 
computer through a terminal or personal computer.The price of mainframe computer is 
several thousand dollars and can be up to several million dollars IBM,Sun and Unisys are 
leading manufacturers of mainframe computers.
EXAMPLE
>IBM S-390
>NEC 610
>DEC !)
>IBM System Z10
Uses of Mainframe Computers:-
mainframe computers are used in large organizations such as banks,educational institutions
and govt.departments.For example,airlines use these computers to maintain flight schedules,
ticket reservation system etc.
Supercomputers:-
Supercomputer is the fastest and the most powerful computer.It is the biggest in size and the
most expensive in price than any other computer.It was first developed in early 1970s. It is
used to perform complex tasks.It has a very large storage capacity and can store several
thousand times more data than average desktop computer.It can process trillions of instruction
in one second .The modern super computer consists of thousands of microprocessors.The
cost of one supercomputer can be up to several billion dollars.
EXAMPLE:-
Roadrunner
Blue Gene
Deep blue
ASCI White
Uses of Supercomputers
Supercomputer is mostly used for weather predication,weapon design and atomic research etc.Supercomputer is also used in business and industry field.Aircraft manufacturers use it to
simulate aircraft and check its performance.Government use a supercomputer for different
calculations and heavy jobs.Many Hollywood movies use it for animation purposes.

Embedded computers:- 

AN embedded computer is designed for special purposes.It works as a component in a 
larger product. these computers are very small and have limited hardware.They perform 
various functions according to the requirements of the product in witch they are embedded.

Embedded computers are used in commonly used products such as.
* Electronics :PDAs,Mobile,Video recorders and DVD players etc.
* Home Devices:Security monitoring system & programmable microwave ovens etc.
* Automobiles:Car engine controller.airbag controller etc
* Process Controllers and Robotic:Machine controllers.blood pressure monitors etc.

The development of electronic computers can be divided into generations depending
upon the technologies. The generations of computer are as follows:

1. First Generation Computer(1942-1955)

The beginning of commercial computer age is from UNIVAC (Universal Automatic
Computer).It was developed by two scientists MAUCHLY and ECHERT at the Census
Department of United Statesin 1947. The first generation computers were used during 1942
-1955. They were based on vacuum tubes.Examples of first generation computers are
ENIVAC and UNIVAC-I etc.

Advantages.
*Vacuum tubes were the only electronic component available during those days.
*Vacuum tubes technology made possible to make electronic digital computers.
*These computers could calculate data in milliseconds.

Disadvantages.
*These computers were very large in size.
*They consumed a large amount of energy.
*They heated very soon due to thousands of vacuum tubes.
*They were not very reliable.
*Ari conditioning was required.
*Constant maintenance was required.
*Non-portable.
*Costly commercial production.
*Limited commercial use.
*Very slow speed.
*Limited programming capabilities.
*Used magnetic drums which provide very less data storage.
*Used punch cards for input.
*No versatile and very faulty.

2. Second Generation Computers(1955-1964)

The second generation computers used transistors. The scientists BELL LABORATORIES
developed transistor in 1947. These scientists include JOHN BARDEEN,WILLIAM
BRATTAIN and WILLIAM SHOCKLEY. The size of computer was decreased by replacing
vacuum tubes by transistors. The examples of second-generation computers are IBM 7094
series, IBM 1400 series and CDC 164 etc.

Advantages.
*Smaller in size as compared to fist generation computers.
*More reliable.
*Used less energy and were not heated.
*Wider commercial.
*Better portability.
*Better speed and could calculate data in microseconds.
*Used faster peripherals like tape drives, magnetic disks, printer etc.
*Used Assembly language instead of machine language.
*Accuracy improved.
Disadvantages.
*Air conditioning was required.
*Constant maintenance was required.
*Commercial production was difficult.
*Only used for specific purposes.
*Costly and not versatile.
*Punch cards were used for input.

3.Third Generation Computers(1964-1975)

  The third generation computers used integrated circuits (IC) Jack Kilby developed the 
 concept of integrated circuit in 1958. It was an important invention in computer filed.The
first IC was invented and used in 1961. The size of an IC is about 1/4 square inch.faster,
more reliable and less expensive. The examples of third-generation computer are IBM 370,
IBM System/360, UNIVAC 9000 etc.

Advantages.
*Smaller in size as compared to previous generation.
*More reliable.
*Used less energy.
*Produced less heat as compared to previous generation computer.
*Better speed and could calculate data in nanoseconds.
*Used fan for heat discharge to prevent damage.
*Maintenance cost was low because hardware failure is rare.
*Totally general purpose.
*Could be used for high-level languages.
*Good storage.
*Versatile to an extent.
*Less expensive.
*Better accuracy.

 4.Fourth Generation Computers(1975-Present)                                                                               

The fourth generation computers started with the invention of microprocessor.The microprocessor contains

thousands OF ICs. Ted Hoff produced the first microprocessor in 1971 for Intel. It was known as Intel 4004. the technology of integrate circuits improved rapidly. The LSI (Large Scale Integration) circuit and VLSI (Very Scale Integration)circuit were deassign. It greatly reduced the size of computer. The size of modernmicroprocessors is usually one square inch. It can contain millions of electronic circuits. The examples of fourth generation computers are Apply Macintosh and IBM PC.

Advantages.
*More powerful and reliable than previous generation.
*Very small in size.
*Less power consumption and less heat generated.
*Fan for heat discharging and thus to keep cold.
*No air conditioning is required.
*Best speed to read instructions i.e. one billionth per second.
*Totally general purpose.
*Commercial production.
*Less need of repairing.
*Cheapest among all generations.
*All types of high-level languages can be used in this type of computers.
Disadvantages.
*The latest technology is required for manufacturing microprocessors.

5. Fifth Generation(Present and Beyond)

Scientists are now working on the 5th generation computers using recent engineering advances.
It is based on the technique of Artificial Intelligence(AI). Computers recent engineering under
stand spoken words instructions and imitate human reasoning. The ability to translate a foreign
language is also moderately possible with

Fifth generation computers.

Scientists are working to increase the speed of the computer.they are trying to create a
computer with real IQ with the help of advanced programming and technologies. The in
modern technologies will revolutionize the computer in future.

The use of computer technology in business provides many facilities . Businessmen are
using computers to interact with their customers anywhere in the world.Many business tasks
are performed more quickly and efficiently.Computers are also help them to reduce the
overall cost of their business. Computer can be used in business as follows:
Marketing:-
Many business organization can use computers for marketing their products .Marketing
applications provide information about the products to customers.Computer is also used to
manage the distribution system, advertising and selling activities. It can also used in deciding 
pricing strategies.
Stock Exchange:-
Stock exchange is the most important place of businessmen. Many stock exchanges use
computers to conduct bids.The stockbrokers perform all trading activities electronically. They
connect with computer where brokers match the buyers with sellers.It reduces cost as no paper
or special building is required to conduct these activities.
Banks:-

The use of computers in banks has provided many benefits. It saves time and provides
convenience for customers. Many banks provide the facility of automated teller machine
(ATM) to withdraw cash directly from machine. Banks provide credit cards that can be used
to purchase different items using the Internet.Banks use computers to maintain customers
accounts.The transaction are handled easily and quickly with computerized system.

Accounts/Payroll
Accounts system is computerized in many organizations.Accounts system maintains daily 
 transaction of a company.It maintains daily books ,trail balance and other information of
 accounts.Payroll system calculates pay, bonus other information of employees.
Departmental Store:-
The use of computer in departmental stores has made the business activities fast and accurate.
the cashier can enter sales data in computer by using barcode reader.The barcode contains
price of a particular item.The computer uses this input to calculate bill.the record of sale is
stored in computer that can be used to analyze accounts and stock inventory.
Fax:-
The user can send fax from computer. Different programs are used for this purpose.The
quality of fax is also higher.It is also possible to receive a fax directly to computer.
Video-Conferencing:-

many companies use video-conferencing to deal with other companies.In video-conferencing
people residing at various places can talk with each other.They can see one another.It is very
useful in this busy age.It prevents a lot of time and costs.
Office Automation:-
Office automation is a process of automating office tasks using computers. many tasks are
performed in an office tasks like decision-making,data manipulation, documents handling and
communication etc.Many computer technologies are used to perform these activities easily.

Computer can be used in education to improve teaching and learning process.It is used in
colleges to provide teaching methods in different ways.It is used to educate students
effectively.Student save data in computer and share other friends.now we see past paper
of any time and any year with the help of Internet.Computer can be used in education in
the following ways:

CBT(computer-based training):-
CBT consists of different program that are supplied on CD-ROM.these programs include
text,graphics,and sound.Audio lectures are recorded on the CDs.CBT is a low cost
solution for education people.you can train a large number of people easily.

Computer-Aided Learning(CAL):-
Computer aided learning is a process of using information technology to help teaching
and learning process.The use of computer can reduce time spent on preparing teaching
material.It also reduces administrative load of  teaching and research the use of multimedia
projector and slides improves the quality of teaching.It also helps learning process.
Distance Learning:-Distance learning is a new learning methodology. computer plays
the key role in this kind of learning. many institutes are providing distance learning programs.
The student dose not need to cone to the institute. The institute provides the reading material
and the student attends virtual classroom.In virtual classroom, the teacher delivers lecture at
his own workplace.The student can attend the lecture at home by connecting to a network.
The student can also ask a questions to the teacher.The answers are given to students by email.

Online Education:-
many websites provide online education.The users can download educational material,books
and tutorials.Some universities provide online lectures for students. students can ask questions
and discuss problems by sending emails to these websites.Student listen teachers face to face
by video calling.

Research:-

Computers are also used for research purposes. Different research scientist can share their
research using the Internet.Many websites are developed for research activities. The students
are young researchers can benefit from such websites.If we need any information about new
research we are visiting these website.

The computer is used in every field of life.It has made different tasks very easy.

Positive Impact of Computer on society:

computer has made a very vital role and impact in our society.It has changed our life.The
use of computer technology has effected every field of life.People are using computers 
for performing different tasks quickly and easily. The use of computer makes different
tasks easier.It saves a lot of time and effort.It also reduces the overall cost to complete a task.
Many organizations are using computer for keeping the records of there costumers. banks
 are also providing the facility of online banking.The costumers can check their account
balance by using the internet. They can also make financial translation online.The transaction
are handled easily and quickly with computerized systems.people are using computer for 
paying their bills. They are getting information from the internet.They also using
computers to manage their home budget etc.

Computer can be used in education field to improve teaching and learning process.
 Computer is used in colleges to provide the methods of teaching in different ways.It is
used to educate the student effectively.Many computer-based educational programs are
available.the students can learn to read, to count, and to speak a foreign language.many
educational games are becoming popular in the students.moreover,the computer is being
 used in every field of life such as medical.business,industry,airline and weather forecasting etc.

Negative Impacts of computer
The use of computer has also created some problems in society which are as follows:

Unemployment:-Different tasks are performed automatically by using computers. it
reduces the need of people and increases unemployment in society

wastage of Time:-Many people use computer without positive purpose.They play games
and chats for a long time.It causes of wastage of time and energy.

Data Security:-The data storage on computer can be accessed by unauthorized persons
through networks.It creates serious problems to data security.
Computer Crime:-people use computer for negative activities.They hack the credit card
numbers of the people and use them for shopping.
Privacy Violation:-The computer are used to store personal data of the people.The privacy
of a person can be violated if the personal and confidential records are not protected properly.
Health Risks:-The improper and prolonged use of a computer can result in injuries or
disorders of the hands.wrists, elbows,eyes,neck and back.The users can avoid health risks by
using the computer in proper position. They must also take regular breaks while using the
computer for a longer time.

Impact on Environment:-The computer manufacturing processes and computer waste are
polluting the environment.The wasted parts of computer can release dangerous toxic materials.
Green computing is a method generated when using a computer.It includes recycling and
regulating manufacturing processes.The used computer must be donated or disposed properly.

Computer can be used as a calculating machine to produce results at a very high speed.
However calculation is not only use of computer.people use computer to solve different 
problems quickly and easily. Computer are available in different shapes and sizes.A
common type of computer system is as follows.
System unit, Monitor,Keyboard,Mouse and Speaker etc.

Characteristics and Advantages of Computer
The imported characteristics of a computer are as follows.
Speed:-Computer processes data at a very high speed.It is much faster then human beings.
A computer can perform billions of calculations in second.For example, the process 769
and 877 can take one or two minutes if it is performed by human beings.However,a computer
can perform millions of such calculations within second.Computer speed is measured in mega
hertz(MHz)or giga hertz(GHz).
Reliability:-computer is very reliable.The electronic components in modern computer
rarely break or fail.
Storage:-Computer can store a large amount of data permanently.People can use this
data at any time.The user can store any type of data in computer.The storage capacity
of computer is increasing rapidly.A computer can store thousands of books easily.
Processing:-A computer can process the given instructions.It can perform different types
of processing like addition,subtraction,multiplication and division.It can also perform logical
functions like coma ring two numbers to decide which one is the bigger etc.
Accuracy:-Accuracy means that computer provides results without any errors.Computer
can process large amounts of data and produce results accurately.The result can be wrong
only if the data given to the computer is not correct.Suppose the average marks of a class
are required.There can be chance of mistake in the result if it is performed by human beings.
However,a computer can produce this result very accurately and quickly.
Recalling:-A computer can recall the storage data and information as and when required.
The data stored in computer can be used at a later time.The computer can recall the required
data in a few seconds.
Control Sequence:-A computer works strictly according to the given instructions.It follows
the same sequence of execution that is given in a program.
Consistency:-Computer works in a consistent way.It does not lose concentration due to
heavy work.It does not become tired or bored.Computer performs all jobs with equal
attention.
Versatile:-Computer is a versatile machine.It can perform different types of tasks.That is
way it is being used in every field of life.Computer is used in hospitals,banks,offices,and
at home.A user can ply games ,listen music, watch movies and use the Internet using a
computer.
Communication:-Most computer today have the capability of communicating with
other computers.We can connect two or more computers by a communication device
such as modem.These computers can share data,instructions,and information.The connected
computers are called network.We can communicate with other people in the world using
network like Internet.
Cost Reductions:-We can perform a difficult task in less time and less cost.For example,
we  may have to hire many people to handle an office.The same work can be performed
by single person with the help of a computer.It reduces the cost