How Search Engines Works

17 July, 2012

What is search Engine?
Basically, a search engine is a software program that searches for sites based on the words that you designate as search terms. Search engines look through their own databases of information in order to find what it is that you are looking for.
When people use the term search engine in relation to the Web, they are usually referring to the actual search forms that searches through databases of HTML documents, initially gathered by a robot.

There are basically three types of search engines: 

1. powered by robots (called crawlers; ants or spiders)
2. powered by human submissions
3. hybrid of above two

Crawler-based search engines are those that use automated software agents (called crawlers) that visit a Web site, read the information on the actual site, read the site's meta tags and also follow the links that the site connects to performing indexing on all linked Web sites as well. The crawler returns all that information back to a central depository, where the data is indexed. The crawler will periodically return to the sites to check for any information that has changed. The frequency with which this happens is determined by the administrators of the search engine.

Human-powered search engines rely on humans to submit information that is subsequently indexed and catalogued. Only information that is submitted is put into the index.

Popular Search Engines:

google

bing

yahoo

blekko

yebol 

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What is Cloud Computing

22 November, 2011

Cloud computing is known as Internet based computing, with shared resources, software and information are provided to computers and other devices based on requirement.  Cloud Computing is a Computing in which services and softwares are provided over the Internet (or “cloud”). Cloud Computing is a technology used to access services offered on the Internet cloud.

Normally cloud computing is a good way to run your business. Instead of running your softwares yourself in your server, Applications run on a shared data center. When you use any application that runs in the cloud, you just log in, change settings, and start using it. Cloud computing is a simple concept , software and services are delivered over the web and through a browser, with no server or client software to install. Cloud computing tools are available any time, anywhere, from any device connecting to the Internet.

The basic concept of cloud computing is using software via the Internet instead of installing it onto your computer. You use an online company to retrieve a particular program. The abstract image of the cloud refers to the Internet. From this cloud, you can find programs that you want to utilize. Through web browser you can access programs from cloud.

There  two main part of cloud computing are the front and back ends. The front end is what the user sees. This involves the network and applications being used. The back end involves the computers, data storage devices, and servers that compose the cloud. Every web application that you’ve ever used, like Gmail, Google Calendar, Hotmail, SalesForce, Dropbox, and Google Docs, are based on “cloud computing”, because when you connect to one of these services, you’re really connecting to a group of servers somewhere out there on the internet.

Cloud Computing Is Dangerous ?

Main fact that cloud computing services are shared all over the world and could be shut down at any time.If any problem in cloud computing server it will affect complete clients connected to that server. The basic fact that you are sharing data with world in big security risk. Example, If I have my server with my data than at least I know that I can protect my data, but if I mix my data with hundreds of servers storing others data as well and if there might be one hole in any application, that will allow a virus to move to the others and it affecting my data. Facebook , Google and other cloud Computing service companies now using more security options for protect user data from external application access.

I hope it is useful for all users. Share your comments about it in the comments box below

Reference:

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How VPN Works

31 July, 2011

VPN ( Virtual Private Network ) using for security in internet networks. It will provide long distance connectivity, between multiple offices of a company by providing secure data transfer and encryption.It can provide security in your video conferencing, as well as
data transfer. It reduces the costs for establishment and maintaining long distance networks. Totally VPN service containing more advantages than normal networks.

What is VPN ?

 

A virtual private network ( VPN )is a special type of wide area network (WAN), which establish connectivity without using leased private lines and makes use of the Internet. It uses the established Internet network, for remote connectivity between long distance offices, workstations or networks. VPN has its own set of softwares, protocols and security constructs which make secure connectivity possible.

How VPN Work ?

 

Normally user double clicks on a software shortcut and the VPN connection window appears. Then user enters a username and password and press connect, the VPN connection is immediately established. Once users are connected to the office network over VPN, they can access files and other resources. After their work press ” Disconnect ” button for disconnect PC from VPN network.

In order to use VPN, your Internet connection should have a static IP address. For establishing of a VPN connection, a secure tunnel is established between VPN server and client. A VPN tunnel is known as a special type of link between a VPN server and a client. The datas transported through the VPN network follows different protocol rules that encrypt the datas over its journey to the VPN server. In the time of reception at the VPN server, the data is again decrypted. Tunnel is a dedicated and secure connection maintained between the VPN server and remote computer. A VPN tunnel may be voluntary or compulsory. Protocols used for VPN tunneling are Layer Two Tunneling Protocol (L2TP), Point-to-Point Tunneling Protocol (PPTP) and Internet Protocol Security (Ipsec).

Advantages of VPN

• VPN network providing secure data transfer and encryption.
• It reduces the costs involved in maintaining long distance networks.
• VPN is useful for remote access.
• VPN allow Access to Mobile Users.
• Several ports for VPN connection (ports: 1194, 53, 5190)

Some VPN Service Providers

• Ultra VPN
• MacroVPN
• Open VPN

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