| Computer Tutorials, Tips and Tricks


Friday, 30 December 2011

Basics of Internet

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Introduction to Internet
The Internet is a worldwide collection of interconnected computer networks that enables businesses, organizations, governments, and individuals to communicate in a variety of ways. One of the most popular ways users communicate on the Internet is by publishing and interacting with Web pages. You can also use the Internet to send and receive e-mail, chat with other users, and transfer files between computers.
Internet Explorer
Types of Connections
Users connect to the Internet through a variety of methods. A relatively inexpensive but slow way to connect is with dialup service, which involves using a modem and a phone line. Faster ways to connect include DSL (digital subscriber line), cable modem, satellite, and ISDN (integrated services digital network). Networks include special wireless transmitters that allow computers to access the Internet wirelessly. Companies that help you connect to the Internet are known as Internet service providers, or ISPs.

Connection Speeds 
Connection speeds play an important part in a user’s Internet experience because slower connections result in slower file transfers and Web page viewing. Dialup connections offer the slowest access to the Internet at up to 56 kilobits per second, or Kbps, followed by ISDN connections at 64 to 128 Kbps. DSL usually offers connection speeds of up to 3 megabits per second, or Mbps, while cable modems can achieve speeds of up to 6 Mbps. A Web page that takes about 20 seconds to download via dialup can take less than a second using a cable modem.

Communication Standards
The Internet infrastructure relies on a variety of protocols that dictate how computers and networks talk to each other. For example, Transmission Control Protocol/Internet Protocol, or TCP/IP, is a set of rules that control how Internet messages flow between computers. Hyper Text Transfer Protocol, or HTTP, is a set of rules that determine how browsers should request Web pages and how server computers should deliver them. Having agreed-upon protocols allows seamless communication among the many different types of computers that connect to the Internet.

The World Wide Web 
The World Wide Web is a giant collection of documents, or pages, stored on computers around the globe. Commonly called the Web, this collection of pages represents a wealth of text, images, audio, and video available to anyone with a computer and an Internet connection. Web pages are stored on servers, which are Internet-connected computers running software that allows them to serve up information to other computers. When you place a text file, image, or other document in a special Web directory on a server, that information is available for other Web users to view.

URLs and Links 
Every page on the Web has a unique address called a URL, which is short for Uniform Resource Locator. A URL looks like this: http://www.example.com/index.html. If you know a page’s URL, you can type it into a Web browser to view that page over the Internet. You can also view pages by way of hyperlinks, or simply links, which are click-able words or images on Web pages. Every link on a Web page is associated with a URL that leads to another page on the Internet. Users can jump from one Web page to another by clicking links.

A Web browser is software that allows you to view and interact with Web pages. When you type a URL or click a link in a Web browser, the browser retrieves the appropriate page from a server on the Internet and displays that page. Microsoft Internet Explorer, Mozilla Firefox, and Apple Safari are the three most popular browsers in use today. Each program has evolved through a number of versions, with newer versions supporting more recent Web features. As you build your pages using HTML code, remember that different browsers may display your pages slightly differently depending on the version.

Thursday, 29 December 2011


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The CRT or display that shows the words, graphics, etc., to the user. It is a critical part of a user’s interface.
A printed circuit board that has (at least) slots to connect cards into.
Often, they also include a CPU and memory.
An input device which has one to three buttons and when you move it, it causes the arrow in a Windows display to move.
An external device that takes commands and data from the computer to place on paper. There are several types of printers: daisy-wheel, matrix, laser, thermal, inkjet, and plotter.
“Random Access Memory“. A pool of storage for the CPU. It can be
written to/read from in any order (unlike a VCR tape which is serial—
you have to wind to the place you want). There are several types of
“Read Only Memory“. Memory that has imprinted in it data and
programs for the CPU which cannot be erased or written to.
An external device that is able to optically read in printed material—kind of like a copier, but it stores the image on the computer instead.
“Uninterruptable Power Supply”. This is a box that is like a surge
protector but will keep you going even if you lose power. You can plug your computer into. If you have a brown- or black-out, this unit will keep you running for 3 minutes to an hour (certainly enough time to save your work and shutdown the computer).
A disk made of plastic and aluminum which can store up to 650MB of
data. Usually these disks cannot be written to, instead they often are
used to distribute software from companies.
Central Processing Unit. The “brain” of the computer. It executes
commands which, eventually, we see as a response to our input.
Without the CPU, the computer is nothing.
Hard disk
A medium to store data for the computer while the power is out. It uses a hard material (typically aluminum).
A typewriter-like tool that has keys. Sends letters or commands to the computer.
A CPU that composes only one chip. Some CPUs may actually be
several square feet is size; but, the microprocessor is designed to be
100% self-contained in a single chip.
A device that will let your computer talk to other computers through the telephone line.
The next generation CD-ROM which will store 10-20x the current
Card Slot
The slots found on the PC motherboard may be one of five types: ISA EISA, MCA, VESA & PCI.. Slower adapters (like I/O boards) can be ISA. But for the best performance, use VESA or PCI for hard drives, CD-ROMs or Video adapters.
Cable Cache
A thick wire that connects the computer to the external device or power. An interface between the CPU and the memory (RAM and ROM). It helps the CPU keep running even though the RAM may be too slow. It does this by keeping a copy of what the processor has read/written.
Most of the time it refers to a card that plugs into the motherboard
adding special capabilities not originally found on the computer. Other times it refers to tools to convert one connector type to another.