TRADE AND COMMERCE.

TRADE AND COMMERCE:

Computers are playing a vital role in the trade and commerce.The introduction of computers has brought about a revolution in this field and contributed greatly to the advancement and development of world business.

In business,computers are used to information processing like word processing filling and assembling numbers and facts associated with general office functions such as accounting, payroll processing,personnel record keeping etc.

In business,computers are provided different facilities in the form of a modern, telex, telefax, e-mail and internet.All the above devices help a businessman in getting his work done in a very short time.Suppose a businessmen has a network of business all over the world.

He exports sports goods to various parts of the world and imports electronic machines.Computers keep him informed about his current business position and the world business market.
   

CLASSIFICATION OF COMPUTERS BY SIZE.

MICRO COMPUTER:
It is the smallest of all the four classes of computers.Some micro computers are tiny special purpose devices dedicated to carrying out a special task,such as controlling the ignition and fuel system in an automobile.But their micro computers are general purpose systems that are used in countless ways.
A micro computer is a computer whose CPU is microprocessor.A microprocessor all of whose components are on a single integrated circuits chips.
A micro computer is also handy and light is weight.It is also called Personal Computer or PC.

MINI COMPUTER:
A mini computer is vary in size from a small desktop model to a unit about the size of a four drawer
 file cabinet.There's obviously an overlap between the more power Personal Computer Systems and the low-end minicomputers in terms of cost and processing capability.
Mini computer is a multi user or shared system.Mini may support dozens or even hundred of terminals,thus they are almost always found in organizations.And in additions to processing the tasks submitted from multiple work stations,mini's can also serve as a communications link between these stations and a central mainframe.

MACRO COMPUTER:
A macro computer or mainframe computer is more powerful than a typical mini.

In macro computer the speed of the CPU is fast,having a huge memory and many different kinds of peripherals can be attached.

Since the size of these computers is very large,they occupy a very large space,their cost is so high that only large companies can afford them.And a group of experts is required to operate them.

SUPER COMPUTER:
The most outstanding class of computers the super computer.
Super computers are more powerful then macro and mini.

The speed of the CPU is maximum.Super computers are the most powerful and most expensive computers made.Only a few of these computing monsters are produced each years because only a few organizations need (and can afford) their processing capabilities.
     
 

CLASSIFICATION.

Computer can be classified in two ways.
-By Purpose
-By Size

BY PURPOSE:
According to purpose computers are classified as under:
-General Purpose Computers.
-Special Purpose Computers.

-GENERAL PURPOSE COMPUTERS:
General purpose computers are those that can store different programs and can be used for countless applications.
The versatility of a general purpose computer is limited by human imagination.
  
-SPECIAL PURPOSE COMPUTERS:
Special purpose computers are those that are designated to perform only one specific task.
Program or instruction set is permanently stored in such a machine.
Although it lacks versatility.It does its single task quickly and efficiently.

BY SIZE:
According to the size computers are classified into the following four categories.
-MICRO COMPUTER.
-MINI COMPUTER.
-MACRO COMPUTER.
-SUPER COMPUTER.
  

 

HISTORY.

 Men from early ages,and throughout the years,have invented and continue to invent machines to help them count.
In the beginning of time,cavemen counted with their fingers and toes.

ABACUS:
About 3000 years age,the Chinese invented the ABACUS.It was the first machine used for counting and calculating.It was made of a wooden frame,metal rods and wooden beads.Each bead has a specific value reading from right to left.
The beads in the first column are worth 1,in the second column the beads are worth 10,in the thirds column the beads are worth 100,etc.addition,subtraction,multiplication and division are performed by moving the beads..

MECHANICAL CALCULATOR:
In 1642,at the age of 19 French mathematician,Blaise Pascal invented a mechanical calculator.Pascal Father's was a tax accountant and he invented a calculator to help his father's job.
This calculator known as "PASCALINE".
The machine consisted as a wooden box that could only add and subtract by means of a series of gears and wheels.
In 1673 a German mathematician G.W.Leibniz constructed a calculator called "LEIBNIZ CALCULATOR".It could do more than just add and subtract.The Leibniz calculator could also multiply,divide and find square roots of numbers.

DIFFERENCE ENGINE: 
In 1823,Charles Babbage design a computing machine based on predefined formula called the difference engine.It consist on ALU.Memory and Control Unit.Unfortunately neither of these machines were completed due to technology at that time was not advanced enough and lack of financial funding.But for his pioneering work on computer he is called the "Father Of Computer".

CARD PUNCHING MACHINE:
In 1890,Herman Holerith develop a machine called card punching and reading machine.It is also called tabulating machine.The tabulating machine used punched cards to read and sort data or information.

MORE INTERNET..

MORE INTERNET:

To connect to the internet following equipment are needed.

COMPUTER:

-Pentium I or Pentium II or above
-64mb RAM or above
-1gm hard disk or larger
-56.6 Kilo bits per second (kbps) modem or above.

PROGRAM:

We require following programs to use the internet.
-Windows
-Internet Software

MODEM:

A modem serves as a medium to exchange information between a computer and the internet.Modem speed is measured in bps (bit per second) speed is the major concern when we are choosing a modem.If the modem is quicker,it will save time as well as money.

There are two types of modems.
-Internal Modem
-External Modem

TELEPHONE LINE:

All the internet travels over the telephone lines.

SPEAKERS:

Speakers allows us to hear music,voice and other sounds generated by the computer.

ISDN LINE:

ISDN or integrated services Digital Network is a line by which data is transmitted over digital telephone line.

ISDN is two to four modems.
Many telephone companies offers these ISDN lines.

 ISP: 

ISP or Internet Service Provider is a company to gain access to the internet against a fee.It can provide you internet access.

 

 

    
   

INTERNET

INTERNET:
 

The internet is a global collection of high-powered computers that are connected to each other with network cables,telephone cables,microwaves dishes,satellites and every kind of electronic equipment currently available.

The internet was launched by the U.S. Defence Department in the late 1960's.By the early 1990's the internet's popularity had grown considerably.

Each computer on the internet stores resources,including documents,sound and video clips,program files,electronic shopping centres,emanations,pictures and anything else that can be stored and presented electrically.When you get connected to the internet,all these resources are available to you.

The internet offers many exciting features.

E-MAIL:

The internet enables us to exchange messages throughout the world with people-friend,colleagues,relatives and even strangers.We happen to meet on the internet E-mail or electronic mail is on exciting feature of the internet as we can send and receives messages over long distance also.On top of that,it is quite fast,easy and inexpensive as well.

 INFORMATION:

Any information on any subject can be obtained easily on the internet.We can have a good browse at news papers, magazines, academic papers, government document, famous speeches, recipes, works by literary figures and what not.

PROGRAM:

The internet offers thousands of free programs.Some of these program are word processors,spreadsheets and games.

ENTERTAINMENT:

The internet offers hundred of simple games free on cost.Children as well as grown ups can enjoy hockey,chess,baseball,cricket and such other games.Internet also offers thousands of movies and dramas for entertainment.

ONLINE SHOPPING:

We can order desired goods and services on the internet.Just setting on comfortable chair at your's home.We need not go out shopping.Items like flowers book,cars,computer programs,CD,DVD and many other things can be bought.