Introduction to Computers and the

Internet

What is a computer?

An "intelligent" machine You tell a person to do a job and the person follows your

“instruction” Similarly, a computer is a machine that follows instructions to

perform various useful tasks. [Show a calculator] It can follow more complex instructions than a

calculator (involving more than just numbers, like, say, playing games with you)

Also has “memory” where data can be stored permanently Cannot “think” on its own, does only what is told. But computers

are useful because they can correctly do what they are told without a break. Similar to a very dumb but hardworking servant.

What can you do with a computer? You type out instructions using a keyboard

and mouse (“input” to the computer) Computer follows your instructions and

shows it to you on the computer monitor (“output” of the computer)

[Show a laptop/computer and point the keyboard, mouse, monitor etc.]

How do I know how to give instructions? You need not write all the instructions, your

computer comes with some common instructions that other people have written.

These set of instructions are called “computer programs” or “software”. You can simply run the programs.

Common programs that computers have Do calculations Write letters/notes Play games with you Many more things

The Power of Many

One man can do some work, but many people as a community can accomplish much more. So also with computers.

A “Computer Network” is a set of computers that can talk to each other and exchange what they know.

How do computers talk? Through wires plugged into them, much like how human beings talk on telephone. They can also talk without wires (“wireless

networks”) like how we talk on cell phones

The Internet

The Internet is a large collection of computers all around the world which are talking to each other.

You can sit in front of any computer that is in this collections, and talk to all other machines through this computer.

Computers on the internet have names and addresses (just like how our homes have addresses) and you can talk to a computer my knowing it’s name (e.g., www.yahoo.com is the name of yahoo’s computer)

What can you do with the Internet? Email

Just like how we send postal mail to each other, computers can send electronic mail (e-mail) to each other

Email is much faster than postal mail, because a computer can talk to any other computer in the world through wires in a few seconds

Get information Many people (e.g., newspapers, schools) put useful

information on their computers and connect them to the internet. You can simply visit type the name of a “website” (i.e., the address of the computer) to see the information it has.

How can I find what I want on the Internet? Suppose some computer far away has some

information you are interested in. How can you find it out and how will you know its name?

Answer: Search sites (www.google.com). They are like Yellow pages. If you tell the website what information you want (e.g., “I want information about computers”), it will tell you the names of all the computers in the world which have this information.

What else can I do with the Internet? E-commerce

Instead of buying and selling things in the market, the buyer and seller can each sit in front of a computer connected to the Internet and trade by talking through the computers.

Software engineers – what do they do? They write programs or software (i.e.,

instructions) that teach a computer how to do some tasks (e.g., play some game with you). This is called “programming” or “software.

Computers have a language that they understand. So software engineers type in commands in that language to the computer.

What is a computer virus? Are computers secure? Computers are prone to burglary like normal homes. When you are careless (e.g., play in rain without

wearing a raincoat), you catch cold. Similarly, when computers are not properly protected (with some protection software), they get “infected” with “computer virus”.

A computer virus is again a set of instructions (i.e., a program) that does bad things to your computer (e.g., steal information). They are written by bad people who want to steal information from your computer.