How Web server works?

This post describes "how web server works".

1. Introduction:

All of you may have question that how and what mechanisms are involved in the Internet. Finally we are receiving our interested information as web-pages with ease of simple efforts (typing context in the search engine). We used to sit in front of computer, right now, viewing this page in a browser. So, when you clicked on the link or typed in its URL for this page, what happened behind the scenes to bring this page onto your screen?
If you've ever been curious about the process, or have ever wanted to know some of the specific mechanisms that allow you to surf the Internet, then read on. In this article, you will learn how Web servers bring pages into your computer-screen-browser (home, school or office). Let's get started!

2.  Process while typing URL in browser:

The steps involved with browser while typing URL in address bar of browser. For example let us take an illustrative url link, as, www.en.wikipedia.org/wiki/Stephen_Hawking. (I considered this URL since, I am curious about his ideology).

The browser decouple the URL into three parts are,

1. The protocol ("http")
2. The server name ("www.en.wikipedia.org")
3. The file name ("wiki/Stephen_Hawking")

Using this information, the browser should get the exact location of the server name( point #2). There fore, the browser communicated with a name server using "http" protocol for obtaining the location of the server name  "www.en.wikipedia.org". Typically, in Internet domain the location will be described with IP Address. There for finally the browser gets the ip address of the server machine. The browser then form a connection to the server located at the IP address on port 80.
 Now, the browser sent a GET request to the server via the HTTP protocol, asking for the file "www.en.wikipedia.org/wiki/Stephen_Hawking" (Note that cookies may be sent from browser to server with the GET request).
The server then sent the HTML file to the browser, namely web-page. (Cookies may also be sent from server to browser at the header for the page.) The browser translates the HTML tags and display on the screen.
Note:

If you find all computer jargons included in this process are new, start to learn web and its associated technologies. The best place to get to know about web-technologies is here. And to understand this whole process in comprehensive details, you need to learn and start with IP addresses, ports, protocols and keep go on.

The next process will be updated soon.

bpmn creation software environment

These days, I am working on business process models (BPM) using standard graphical notation called bpmn (business process model and notation). Brief summary of bpmn and its usage for myriad applications in several domain will be posted soon. Mean while, in this post I am giving few sources for variety softwares in which we can create and manipulate bpmn diagrams.

BPMN initiated by the consortium OMG and also there is a bpmn-community is running by the researchers at Business Process Technology Group of Hasso Plattner Institut, University of Potsdam. The BPMN-community is an open and free platform for the exchange around the Business Process Model Notation. The latest version of BPMN 2.0, is provided since 2011 offically.

Few software sources:

1. sparx EA, is windows compatible software, we can model business process using bpmn elements. The creation of business process models with bpmn in this software also facilitates the take advantages of other modules of sparx systems. But this software is proprietary.
     " This software can be use in linux with the help of wine."
2. dia, is linux based software and open-source.  Terminal command to install is >> sudo apt-get install dia.
3. Iyopro. is actually a compony with freeware. It is great for those who want to feel a more “Window” atmosphere, because the software is design to be deployed as if you operate in Window. The artifacts provided are the latest version of BPMN 2.0. Membership is required. 
4. yED Graph Editor is windows, linux and mac based software and now-days they are also providing on-line service with the option named "launch" the software. They recently released yEd 3.9 version on Jan 31, 2012 with bpmn 2.0 graphical elements compatible

English Letter Writing Practice

This post describes tips for writing formal letters in English and also given related url links will help you in this regard.

I am not here to explain again how to write formal letter writing, since, now we are in 2012 phase and internet is full up with myriad of tutorials on-line. Therefore, as of now, I have found few links that are given below, which are helpful in writing formal letters

sources for writing letters:
1. click here : Guide to Basic Business Letters
2. click here : Letter writing guide with sample examples.
3. click here : Writing business letter useful phrases