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Introduction to Networks

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Introduction to Networks Powered By Docstoc
					Networks
In general, the term network can refer to any interconnected group or system. More specifically, a network is any method of sharing information between two systems (human or mechanical). Benefits of Networking One of the best advantages to networking your home PC's is that you can share printers and other peripherals between the networked units. You can also share applications across the network and share the hard drive resources.

Topology
Topology refers to the way in which the network of computers is connected. Each topology is suited to specific tasks and has its own advantages and disadvantages. The choice of topology is dependent upon 1. Type and number of equipment being used 2. Planned applications and rate of data transfers 3. Cost

TOPOLOGIES

The Following are the major types of topologies

Bus Ring

Star
Tree Mesh

INTERNET
Internet is defined as Network of Networks. The Internet links are computer networks all over the world so that users can share resources and communicate with each other. Some Important Terms Internet Service Provider An Internet service provider (abbr. ISP, also called Internet access provider or IAP) is a company or business that provides access to the Internet and related services. Modem (from modulatordemodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.

APPLICATION SOFTWARES CONTINUED
Browser
An Internet browser is a program that lets you navigate the World Wide Web. A browser displays web pages, keeps track of where you've been, and remembers the places you want to return to. Internet Explorer is by far the most popular browser, though there are many others around. Netscape was once the dominant browser and is still used, but it is falling further behind in market share all the time.

Antivirus
Antivirus are computer programs that attempt to identify, neutralize or eliminate malicious software. Antivirus is so named because the earliest examples were designed exclusively to combat computer viruses.

Vital Resources & Information Under Siege

Important Terms Related to Internet
Gopher
Gopher is a client/server system that allows you to access many Internet resources simply by making selections from a sequence of menus. Each time you make a selection, Gopher carries out your request to the computer that contains the information and "serves" it up.

World Wide Web (WWW)
The World Wide Web (commonly shortened to the Web) is a system of interlinked hypertext documents accessed via the Internet. With a Web browser, a user views Web pages that may contain text, images, videos, and other multimedia and navigates between them using hyperlinks.

Uniform Resource Locators, or URLs:
A Uniform Resource Locator, or URL is the address of a document you'll find on the WWW. Your WWW browser interprets the information in the URL in order to connect to the proper Internet server and to retrieve your desired document.

Bandwidth - The capacity of an electronic line, such as a communications
network or computer channel, to transmit bits per second (bps).

Important Terms Continued
Search Engines
The World Wide Web is "indexed" through the use of search engines, which are also referred to as "spiders," "robots," "crawlers," or "worms". These search engines comb through the Web documents, identifying text that is the basis for keyword searching.

Bookmarks & Favorites
Have you ever visited a website and then could not remember how to find it again? Or maybe you are tired typing the name of your favorites web site over and over again. Well, the simple solution to this problem is to create bookmarks. You can Bookmark a site (Netscape) or add it to your Favorites list (Internet Explorer). Book marking simply saves the address of the site in your web browser and adds it to a list in your Favorites Menu (Internet Explorer). To visit the site again, all you need is to select the site's name from the menu and your browser will open the page.

Home Page
The first page that loads when you start your web browser is called your Home Page. You can set your Home Page to be your favorite site or a site you use often.

Important Terms Continued
History
Have you ever visited a website and later, you just could not remember the address? Yup, it happens to all of us. Fortunately you can check your browser's history. The History stores the address of websites you visited from as far back as a few weeks.

Address Bar
The Address Bar (Internet Explorer) or Location Bar (Netscape) displays the web address of each web page you visit. Every web page has a unique address. If you know the address of a web page that you would like to visit, enter the address in the bar and hit enter.

LAN – Local Area Networks is a computer network covering a small

geographic area, like a home, office, or group of buildings e.g. a school. MAN – Metropolitan Area Networks are large computer networks usually spanning a city WAN - Wide Area Networks is a computer network that covers a broad area (i.e., any network whose communications links cross regional, or national boundaries )

HTML -

A type of text code in Hypertext Markup Language which, when embedded in a document, allows that document to be read and distributed across the Internet.

Important Terms Continued
Portal A Web site "gateway" that provides multiple services, which could include Web searching capability, news, free-email, discussion groups, online shopping, references and other services. a text-based computer conference over the Internet between two or more people who must be online at the same time. When you send an message the receiver is instantly notified that she/he has a message.

Chatting

Web Server
A computer connected to the Internet for the purpose of serving a web site's web pages to visitors on the World Wide Web.

UPLOAD
With uploading, you take a file from your computer and send it to a computer on the internet (or a server)

DOWNLOAD
To copy something from a primary source to a more peripheral one, as in saving something found on the Web (currently located on its server) to diskette or to a file on your local hard drive.

How to Read Web Address or URL
Web addresses
A Web address, also referred to as a URL (Uniform Resource Locator), is the location or pathway to a website. For example, the web address for this website is http://www.google.com. A web address is actually made up of four parts. Most people only need to use the last 3. Lets use google.com's web address for an illustration:

http:// — Http is the Protocol name. (discussed Later) www — indicates the Location of the site. The WWW indicates that the site is located on the World Wide Web. All sites however, are not on the World Wide Web. Google — This is the Site Name. Site names must names never have spaces in them. .com — the site is commercial. Here are some other types you may find: edu — the site is educational .org — the site is organization .gov — the site is government .net — the site is Network

Electronic Mail i.e. Email
Email
Email, or electronic mail, is becoming more and more popular as people learn to communicate again with written words. For many purposes it is superior to a phone call because you don't have to catch the person in and you can get straight to the point. No time is wasted on casual conversation. Email basic functionality which allow you to: *send and receive mail messages *save your messages in a file *print mail messages *reply to mail messages *attach a file to a mail message Sample Internet Address: username@google.com The Email address has three parts: 1.a user name [username in the example above] 2.an "at" sign (@) 3.the address of the user's mail server

Email Continued
Some Basic Terms Used while using Email…
TO When you send an e-mail message, you typically type the recipient's address in the "To:―

CC When you use CC option, the recipient’s will be knowing to all which people email is send. Their respective address will be shown to all.
BCC When you use BCC option, the recipient’s will not be able know to all which people email is has been send. Reply you click this button when you want to reply the received mail. Forward you click this button when you want to send the received mail to other users. Subject The heading of the mail. Body The matter of the mail. Send you click this button when you want to send the mail. Draft you click this button when you want to save the mail for sending it later

Email Continued
Address Book
Address book or a is a book or a database used for storing entries called Email contacts & Addresses.

Sites that provide Free Emails 1. www.gmail.com 2. www.yahoo.com 3. www.rediff.com 4. www.aol.com 5. www.indiatimes.com
Types of Emails 1. Text Mail. 2. Voice Mail.

Email Application Programs 1. Outlook Express 2. Microsoft Outlook 3. Eudora

PROTOCOL
Protocol is the special set of rules that controls and governs the
telecommunication connection used by two computers when they communicate to each other. is a network protocol used to transfer data from one computer to another through a network, such as over the Internet. is a communications protocol for the transfer of information on intranets and the World Wide Web. Its original purpose was to provide a way to publish and retrieve hypertext pages over the Internet. is the standard for e-mail

File Transfer Protocol (FTP)

Hypertext Transfer Protocol (HTTP)

Simple Mail Transfer Protocol (SMTP)
transmissions across the Internet.

Transmission Control Protocol (TCP)

provides reliable, in-order delivery of a stream of bytes, making it suitable for applications like file transfer and e-mail.

The boot sector for PC-compatible computers is located at track zero. In DOS, this code will read the DOS BIOS into memory and execute it. The BIOS is located in IBMBIO.COM on DR DOS and PC DOS, and IO.SYS on MS DOS. The BIOS will then load the DOS kernel, located in IBMDOS.COM (PC DOS or DR DOS) or MSDOS.SYS (MS DOS). In the Windows DOS versions (MS DOS 7 and 8), the BIOS and kernel are combined in IO.SYS, and MSDOS.SYS is a text configuration file. The kernel then executes the CONFIG.SYS file. In CONFIG.SYS, the SHELL command specifies the location of the shell (typically COMMAND.COM). The shell will then launch, and open a startup batch file (typically AUTOEXEC.BAT).[9]


				
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