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What computers can do?

Computers can perform a wide range of operations. As a matter of fact, in today's competitive world, one cannot think of doing anything without the help of the computers. From household to offices, department stores and shopping malls, computers have prevailed everywhere.

A Laptop Computer

What can you do with computers?
People use computers to keep and analyze records, manage researches and projects etc in the workplace. At home, computers can be used to find information, store various data like pictures, music and videos, track finances, play games, communicate with other people around the world via the internet and much more. With Internet access, you can communicate with people all over the world and find a vast amount of information.


What is web?

The World Wide Web (usually called the web, or web) is a vast storage of information. The web displays most of the information in a visually delightful format, hence the reason for its popularity. Headlines, text, and pictures can be combined on a single webpage; similar to the pages in a magazine, along with sounds and videos. A website is a collection of interconnected webpages. The web contains millions of websites and billions of webpages, and millions of websites are uploaded each day.

Example of a webpage (
Example of a webpage (

Exploring the web is known as Surfing. Anyone surfing the web can find information about almost anything or any topic imaginable. You can read news or stories and movies reviews, book a hotel or an air ticket, view maps, get current weather and future weather forecast, view pictures or videos, play games or read the game reviews, etc. Almost all the companies, agencies, libraries and museums today have their own websites with information about their products and services or collections. You can also search and purchase products online - books, music, toys, clothing, electronics, and much more. You can also buy and sell used items through websites that use auction-style bidding. For example, see this website.



E‑mail (Electronic mail) is an electronic means of sending the letter to someone. When you send an e‑mail message, it arrives almost instantly in the recipient's e‑mail inbox. E-mail messages can be sent to many people simultaneously,  and you can save, print, and forward the e‑mail to others. You can send almost any type of file in an e‑mail message; documents, pictures, music, videos etc. And with e‑mail, you don't need a postage stamp (how cool is that!!).


Instant messaging

Instant messaging is having a real - time conversation with another person who is far away from you. When you send an instant message, the message is immediately visible to all participants of the conversation. Unlike e‑mail where the message is delivered at any time and the recipient may view it at anytime, for instant messaging, all participants of the conversation have to be online (connected to the Internet) and in front of their computers at the same time. Communicating by means of instant messaging is also known as chatting.


Pictures, music, and movies

If you have a digital camera, you can move your pictures from the camera to your computer. Then you can print them, create slide shows, or share them with others by e‑mail or by posting them on a website. You can also listen to music on your computer, either by importing music from audio CDs or by purchasing songs from a music website. Or, you can tune in to one of the thousands of radio stations that broadcast over the Internet. If your computer comes with a DVD player, you can watch movies too.



Everybody likes to play games. There are thousands of computer games in every category imaginable, which you can play on your computer. Get behind the wheel of a over-speeding car, battle frightening monsters in a dungeon, or control civilizations and empires! Many games allow the users to compete with other players around the world via the Internet.
There are also some games which can be played online only - called online games. Such games can be played with the computer or with other opponents from around the world. You can also earn money from these games if you win or even if you are close to win!

Inside the computer

Whats inside the computer?

Following picture shows a view of the inner organs of a computer.

Inside the computer
Insde a typical computer

Power Supply:

Power supply
Power supply
A power supply or SMPS (Switched Mode Power Supply) converts AC signal to low voltage regulated DC signal for the use of components inside the computer. Most modern desktop computer power supplies are ATX power supplies, which always provides a 5 V voltage although it is connected to the mains supply. ATX power supply can be turned ON and OFF by a signal from the computer.


Processor Fan. The actual processor is below this fan

     A processor is a multipurpose, programmable device that takes data from the user, processes it according to the instructions stored in its memory, and gives the result of the processing as output. In the earlier days of computer history, processors were constructed in small and medium scale IC forms, consisting of tens to few hundred transistors. Such processors were too much limited in their operations, and power consumption was also high. The first processors appeared in early 1970s, which were used for digital calculators, terminals, printers and other simple type of automatic systems.
intel 4004 processor
intel 4004 processor

     The first commercial processor was intel 4004, whose price was $60. It was originally designed by intel for desktop calculators for a Japanese calculator company, with high performance and rich features. It was a 4-bit processor, with a clock speed of 740 kHz. Since the intel 4004, the history of processors has undergone a vast improvement in size, performance, quality, power consumption, etc. and today we have intel i7 the most advanced processor up to date.

Modern Processor

Hard disk:

Hard disk
Hard Disk
A hard disk drive is a data storage device for a computer. It is used for storing the digital information processed by the computer for later use. A hard disk usually consists of rapidly rotating disks (or "plates") which are coated with magnetic material so that data can be stored in digital form. The magnetic storage of digital data is not deleted even when the power to the disk is cut off because data is stored as "magnetic cells" on the surface of the disk plates.

A simple hard disk
A simple hard disk

Exploded view of a hard disk
Exploded view of a hard disk

PCI Slots:

PCI Slots
PCI Slots

PCI (Peripheral Components Interconnect) are the slots on a motherboard where extra components in a computer can be inserted. It is a type of bus; the terminal where other components are inserted.
If, for example, you want to insert a TV card (a device that allows to watch TV on your PC), which does not usually come with your computer, you can insert it in the PCI bus and watch TV. Modems and NICs (Network Interface Card) are other devices that are usually inserted in a PCI slot.

OSI Model (contd ...)

 Transport layer

The transport layer provides the flow of data between computers, as the name suggests. The Transmission Control Protocol, TCP and the User Datagram Protocol reside in this layer. In the transport layer, the data is segmented into parts to achieve a steady flow so that the differences in connection bandwidth between the host computers does not matter in the circulation of the data through the network.

Network layer
The Network Layer helps in transporting the data between the networks. At the beginning of the segments a network header is placed, which consists of the IP addresses of the sender and the receiver terminals. This header remains constant which is just read during the process of communication. The IP or Network trailer is also present at the end of the package, which contains the checksum to validate the data that is transferred between the networks. The Network Layer is employed by the routers to handle the network addresses.

Data link Layer
The data link layer takes input bits from layer one and arranges them into data structures called frames. It uses a frame header containing the sender and receiver addresses. These values do not remain constant and change while passing through the network nodes, routers or servers.

Physical Layer
The Physical Layer consists of the electrical part of the process of communication, the binary signals or bits that are transmitted and received in the process of exchange of data during the communication. The binary signal is a combination of 1's and 0's that may be repeated.